RFID transponder chip modules with a band of the antenna extending inward

ABSTRACT

The planar antenna (PA) of a transponder chip module (TCM) may have a U-shaped portion so that an outer end (OE) of the antenna may be positioned close to an RFID chip (IC) disposed at a central area of a module tape (MT) for the transponder chip module. A module tape (MT 2 ) may have contact pads (CP) on one side thereof and a connection bridge (CBR) on another side thereof, and may be joined with a module tape (MT 1 ) having a planar antenna (PA). Metal of a conductive layer (CL) within a conductive element such as a coupling frame (CF) or a planar antenna (PA) may be scribed to have many small segments. A metal sheet may be stamped to have contact side metallization, and joined with a module tape (MT) having a planar antenna (PA).

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from and is a continuation-in-part(“CIP”) or nonprovisional filing of the following US applications:

-   a nonprovisional of 62/104,759 filed 18 Jan. 2015-   a nonprovisional of 62/102,103 filed 12 Jan. 2015-   a nonprovisional of 62/096,559 filed 24 Dec. 2014-   a nonprovisional of 62/088,598 filed 7 Dec. 2014-   a nonprovisional of 62/048,373 filed 10 Sep. 2014-   a nonprovisional of 62/039,562 filed 20 Aug. 2014-   a continuation-in-part of Ser. No. 14/551,376 filed 24 Nov. 2014-   a nonprovisional of 62/080,332 filed 16 Nov. 2014-   a nonprovisional of 62/061,689 filed 8 Oct. 2014-   a nonprovisional of 62/044,394 filed 1 Sep. 2014-   a continuation-in-part of Ser. No. 14/492,113 filed 22 Sep. 2014    (20150021403, 22 Jan. 2015)-   a continuation-in-part of Ser. No. 14/465,815 filed 21 Aug. 2014    (20140361086, 11 Dec. 2014)-   a nonprovisional of 62/035,430 filed 10 Aug. 2014-   a continuation-in-part of Ser. No. 14/523,993 filed 27 Oct. 2014-   a non-provisional of 61/945,689 filed 27 Feb. 2014-   a CIP of Ser. No. 14/281,876 filed 19 May 2014 (20140284386, 25    Sep. 2014) which claims priority from    -   61/937,541 filed 9 Feb. 2014    -   61/920,737 filed 25 Dec. 2013-   a non-provisional of 62/028,302 filed 23 Jul. 2014-   a non-provisional of 62/023,874 filed 12 Jul. 2014-   a CIP of Ser. No. 14/078,527 filed 13 Nov. 2013 (20140104133, 17    Apr. 2014) which claims priority from    -   61/875,046 filed 8 Sep. 2013    -   61/827,754 filed 28 May 2013-   a non-provisional of 61/950,020 filed 8 Mar. 2014-   a non-provisional of 62/021,112 filed 5 Jul. 2014-   a CIP of Ser. No. 14/552,504 filed 25 Nov. 2014, which is a    continuation of    -   Ser. No. 13/744,686 18 Jan. 2013 (20130126622, 23 May 2013)-   a CIP of Ser. No. 14/259,187 filed 23 Apr. 2014 (20140284387, 25    Sep. 2014), which is a continuation of    -   Ser. No. 13/931,828 29 Jun. 2013 (U.S. Pat. No. 8,708,240, 29        Apr. 2014) a continuation of        -   Ser. No. 13/205,600 filed 8 Aug. 2011 (U.S. Pat. No.            8,474,726, 2 Jul. 2013)

TECHNICAL FIELD

The disclosure relates to RFID devices including “secure documents” or“RFID tags” such as electronic passports, electronic ID cards andsmartcards (or payment cards, electronic tickets, chip cards and thelike) having RFID (radio frequency identification) chips or chip modules(CM) capable of operating in a “contactless” mode (ISO 14443 or NFC/ISO15693) including dual interface (DI) smartcards and secure documentswhich can also operate in contact mode (ISO 7816-2) and, moreparticularly, to transponder chip modules (TCMs) suitable forimplanting, insertion or placement in secure documents, such assmartcards.

The techniques disclosed herein may also be applicable to RFID devicesincluding “non-secure smartcards and tags” such as contactless cards inthe form of keycards, access control cards, security badges, wearabledevices, mobile phones, tokens, small form factor tags, data carriersand the like operating in close proximity with a contactless reader.

BACKGROUND

A dual interface (DI or DIF) smartcard (or smart card; SC) may generallycomprise:

-   -   an antenna module (AM) having a module antenna (MA) for        contactless operation and contact pads (CP) for contact        operation,    -   a card body (CB) having layers of plastic or metal, or        combinations thereof, and    -   a booster antenna (BA) disposed in the card body (or “inlay”).        Some examples of smart cards having booster antennas are        disclosed in U.S. Ser. No. 14/020,884 filed 8 Sep. 2013 (US        20140091149, 3 Apr. 2014)

The antenna module (AM), which may be referred to as a transponder chipmodule (TCM) or RFID module may generally comprise:

-   -   a module tape (MT) or chip carrier tape (CCT), more generally,        simply a “substrate”;    -   a contact pad array (CPA) comprising 6 or 8 contact pads (CP, or        “ISO pads”) disposed on a “face up side” or “contact side” (or        surface) of the module tape (MT), for interfacing with a contact        reader in a contact mode (ISO 7816);    -   an RFID chip (CM, IC) which may be a bare, unpackaged silicon        die or a chip module (a die with leadframe, interposer, carrier        or the like) disposed on a “face down side” or “bond side” or        “chip side” (or surface) of the module tape (MT);    -   a module antenna (MA) or antenna structure (AS) disposed on the        face down side of the module tape (MT) for implementing a        contactless interface, such as ISO 14443 and NFC/ISO 15693 with        a contactless reader or other RFID device.

An antenna module (AM) which may be able to operate without a boosterantenna (BA) in the card body (CB) may be referred to as a transponderchip module (TCM), or as a transponder IC module.

The antenna module (AM) or transponder chip module (TCM) may begenerally rectangular, having four sides, and measuring approximately8.2 mm×10.8 mm for a 6-contact module and 11.8 mm×13.0 mm for an8-contact module. Alternatively, the transponder chip module (TCM) maybe round, elliptical, or other non-rectangular shape. When operating ina contactless mode, the antenna module (AM) or transponder chip module(TCM) may be powered by RF from an external RFID reader, and may alsocommunicate by RF with the external RFID reader.

A module antenna (MA) may be disposed on the module tape (MT) forimplementing a contactless interface, such as ISO 14443 and NFC/ISO15693. Contact pads (CP) may be disposed on the module tape (MT) forimplementing a contact interface, such as ISO 7816. The contact pads(CP) may or may not be perforated. The module tape (MT) may comprise apattern of interconnects (conductive traces and pads) to which the RFIDchip (CM, IC) and contact pads (CP) may be connected. The module tape(MT) may be “single-sided”, having a conductive layer (or cladding, orfoil) on only one side thereof, such as the “face-up” side thereof, suchas for the contact pads (CP). The module tape (MT) may be“double-sided”, having conductive layers (or claddings, or foils) onboth sides thereof. A conductive layer on the “face-down” side of themodule tape (MT) may be etched to form a module antenna (MA) having anumber of tracks (traces) separated by spaces.

The module antenna (MA) may be wire-wound, or etched, for example:

-   -   The module antenna (MA) may comprise several turns of wire, such        as 50 μm diameter insulated wire. Reference may be made to U.S.        Pat. No. 6,378,774 (2002, Toppan), for example FIGS. 12A, B        thereof.    -   The module antenna (MA) may be a chemically-etched planar        antenna (PA) structure. Reference may be made to U.S. Pat. No.        8,100,337 (2012, SPS), for example FIG. 3 thereof.    -   The module antenna (MA) may comprise a laser-etched planar        antenna (PA) structure (LES). Reference may be made to U.S. Ser.        No. 14/281,876 filed 19 May 2014 (US 20140284386, 25 Sep. 2014),        incorporated by reference herein.

A planar antenna (PA) structure, or simply “planar antenna (PA)”,whether chemically-etched (CES) or laser-etched (LES) is a type ofantenna structure (AS) and may comprise a long conductive trace or trackhaving two ends, in the form of a planar, rectangular spiral, disposedin an outer area of a module tape (MT), surrounding the RFID chip on theface-down side of the module tape. This will result in a number oftraces or tracks (actually, one long spiraling trace or track),separated by spaces (actually, one long spiraling space). The track (ortrace) width may be approximately 100 μm. Generally, with laser etching,the track width may be made narrower and the spaces between traces canbe made smaller than with chemical etching. For example, whereas withchemical etching the spaces between tracks may be limited to 100 μm,with laser etching spacing of 25 μm or less may be achieved. The planarantenna may be fabricated on other than the module tape, such as on aseparate substrate.

The (two) ends of the module antenna (MA) may be connected, eitherdirectly or indirectly to corresponding terminals (LA, LB) of the RFIDchip (IC, CM). For example, one or both ends of the module antenna (MA)may be connected to bond pads or interconnect traces on the face-downside of the module tape (MT), to which the terminals of the RFID chip(IC, CM) may also be connected.

Alternatively, one or both ends of the module antenna (MA) may beconnected (to the RFID chip) via electrically conductive structures,which may be referred to as “contact bridges” or “connection bridges”,disposed on the face-up side of the module tape (MT), and which may beformed from the same conductive layer as the contact pads (CP). Someexamples of connection bridges may be found in

-   -   US 20130146670 (2013 Jun. 13, Grieshofer et al; “Infineon”)    -   commonly-owned, copending US 20140104133 published 17 Apr. 2014    -   commonly-owned, copending U.S. Ser. No. 14/523,993 filed 27 Oct.        2014    -   commonly-owned, copending U.S. Ser. No. 14/551,376 filed 24 Nov.        2014

The antenna (or antenna structure AS) may be laser etched from a copperlayer (cladding or foil), which may have a thickness of approximately 18μm-35 μm, but may be approximately 12 μm, which may be less than theskin depth of copper (˜18 μm), forming a number of tracks separated by adistance approximately equal to the width of the laser beam, or dictatedby the kerf of the laser, such as approximately 25 μm. (The laser burnsaway a portion of material when it cuts through. This is known as thelaser kerf. The kerf size will be greater than the theoretical spot sizeof the focused laser beam and will depend on the material properties ofthe target and laser settings.) Subsequent to laser etching, the antennastructure may be plated, which may reduce the distance between tracks toapproximately 20 μm (for example). This may result in increasedperformance of the antenna structure, and the overall antenna module AM(or transponder chip module (TCM)), and reduce performance constraintson the performance of a booster antenna (BA) in the card body (CB) ofthe smartcard (SC).

A module antenna (MA) connected to an RFID chip (CM), typically on asubstrate or module tape (MT), may be referred to as a “transponder”.Generally, such a transponder may be a “passive” transponder which doesnot have its own power source (e.g., battery), but rather which receives(harvests) its operating power from an external reader (interrogator)rather, for example, from a battery. An “active transponder” may haveits own internal power source, such as a battery.

SUMMARY

It is a general object of the invention to provide improved transponderchip modules (TCM) and improved techniques for manufacturing transponderchip modules (TCM), and also to provide improved coupling of smartcards(as an example of secure documents, RFID devices and the like, includingdual-interface smartcards and metal or metallized smartcards) with acontactless reader.

As used herein, a transponder chip module may generally comprise an RFIDchip and a module antenna disposed on one (face-down) side of a moduletape, and contact pads on an opposite (face-up) side of the module tape.Such a transponder chip module, having both an antenna for contactlesscommunication with an external reader and contact pads for making aphysical connection with an external reader may be referred to as a“dual-interface” transponder chip module. Some embodiments describedherein may be directed to transponder chip modules having only acontactless interface (no contact pads for a contact interface).

Various techniques may be disclosed herein to improve the constructionand performance of transponder chip modules, such as (but not limitedto):

-   -   the use of connection bridges extending both parallel to and        perpendicular to the insertion direction.    -   coupling frames incorporated into the body of a smart card    -   coupling frames incorporated into the module tape of the        transponder chip module    -   using multiple antenna structures to form the module antenna    -   forming the module antenna (planar antenna) on an antenna        substrate which is separate from the module tape carrying the        contact pads (and connection bridges)    -   segmenting metal remaining within an interior area of an etched        planar antenna    -   making connections through the module tape to the undersides of        isolated conductive features such as contact pads or connection        bridges located on the face-up side of the module tape    -   stamped leadframe-type techniques for forming the isolated metal        features    -   modifying the geometry of the planar antenna to have a U-shaped        portion along one of its sides so that its outer end may be        closer to the RFID chip for wire bonding (wire bonding), thereby        avoiding the need for a connection bridge.    -   disposing the contact pads in an inner area of the module tape,        and providing additional isolated conductive features in an        outer area of the module tape, with the planar antenna located        under the additional isolated conductive features.

According to the invention, generally, the planar antenna (PA) of atransponder chip module (TCM) may have a U-shaped portion so that anouter end (OE) of the antenna may be positioned close to an RFID chip(IC) disposed at a central area of a module tape (MT) for thetransponder chip module. A module tape (MT2) may have contact pads (CP)on one side thereof and a connection bridge (CBR) on another sidethereof, and may be joined with a module tape (MT1) having a planarantenna (PA). Metal of a conductive layer (CL) within a conductiveelement such as a coupling frame (CF, 424) or a planar antenna (PA) maybe scribed to have many small segments. A metal sheet may be stamped tohave contact side metallization, and joined with a module tape (MT)having a planar antenna (PA).

According to some embodiments (examples) of the invention, a transponderchip module (TCM) may comprise: a module tape (MT); contact pads (CP)disposed on a face-up side of the module tape; a planar antenna (PA)disposed on a face-down side of the module tape, and extending in a bandin a rectangular spiral pattern around an outer area of the module tape,wherein the antenna has an inner end (IE) and an outer end (OE); and maybe characterized in that: a portion of the band of the planar antennaextends inward, towards a central area of the module tape, so that itsouter end is not more than approximately 3 mm from an RFID chip (IC)disposed in the central area. At least the outer end of the planarantenna may be connected by wire-bonding to the RFID chip. The portionof the planar antenna may extend into an area on the face-down side ofthe module tape corresponding with an area on the face-up side of themodule tape between two contact pads. The planar antenna is laser etchedas a long track having a number of turns; the track may have a width ofapproximately 100 μm or less; and a space between turns of the track maybe approximately 25 μm or less.

According to some embodiments (examples) of the invention, a planarantenna (PA) for a transponder chip module (TCM) having the form of arectangular spiral conductive trace having several turns, an inner end(IE) and an outer end (OE), and suitable to be disposed in a rectangularannular outer area of a module tape (MT) may be characterized in that: ashape of at least one side of the antenna is modified so that the outerend (OE) of the antenna is positioned closer to a center of the moduletape than the remainder of the outermost turn of the antenna. The outerend may be positioned closer to the center of the module tape than manyor all of the turns of the antenna, including closer to the center thanthe innermost turn of the antenna. The outer end may be positionedcloser to the center of the module tape than many or all of the turns ofthe antenna, including closer to the center than the innermost turn ofthe antenna.

According to some embodiments (examples) of the invention, a method ofconnecting a planar antenna (PA) of a transponder chip module (TCM) toan RFID chip (IC) in the module may comprise: connecting an inner end(IE) of the planar antenna by wire bonding to the RFID chip; and may becharacterized by: connecting an outer end (OE) of the planar antenna bywire bonding to the RFID chip.

According to some embodiments (examples) of the invention, a transponderchip module (TCM) may comprise: a first module tape (MT1,) having anantenna structure (AS) on a surface thereof; and a second module tape(MT2) having contact pads (CP) on first surface thereof and a connectionbridge (CBR) on a second surface thereof; wherein the second module tapeis joined to the first module tape. The transponder chip module mayfurther comprise: conductive elements extending through the secondmodule tape and aligned with at least some of the contact pads. Thetransponder chip module may further comprise: through holes (TH)extending through the first module tape and aligned with the conductiveelements extending through the second module tape. The transponder chipmodule may further comprise: through holes (TH) extending through thefirst module tape and aligned with outer and inner portions of theconnection bridge. The transponder chip module may further comprise: anopening (OP) extending through the first module tape allowing mountingof an RFID chip (IC) on the second module tape.

According to some embodiments (examples) of the invention, a module tape(MT2) for a transponder chip module (TCM) may comprise: contact pads(CP) on first surface thereof; and a connection bridge (CBR) on a secondsurface thereof. The module tape may further comprise: an other moduletape (MT1) having an antenna structure (AS) on a surface thereof;wherein the other module tape (MT1) is joined to the module tape (MT2).

According to some embodiments (examples) of the invention, a method ofmaking a transponder chip module (TCM) may comprise: providing a firstmodule tape (MT1) having an antenna structure (AS) on a surface thereof;providing a second module tape (MT2) having contact pads (CP) on firstsurface thereof and a connection bridge (CBR) on a second surfacethereof; and joining the second module tape (MT2) joined to the firstmodule tape (MT1). The method may further comprise: providing conductiveelements extending through the second module tape and aligned with atleast some of the contact pads. The method may further comprise:providing through holes (TH) extending through the first module tape andaligned with the conductive elements extending through the second moduletape. The method may further comprise: providing through holes (TH)extending through the first module tape (MT1) and aligned with outer andinner portions of the connection bridge. The method may furthercomprise: providing an opening (OP) extending through the first moduletape allowing mounting of an RFID chip (IC) on the second module tape.

According to some embodiments (examples) of the invention, a method offorming a planar antenna (PA) for a transponder chip module (TCM) maycomprise: etching a conductive layer (CL) in a rectangular spiralpattern having a track exhibiting a number of turns and having aplurality of traces separated by spaces; and segmenting the conductivelayer in an area within an interior of the pattern to have a pluralityof relatively small isolated conductive structures rather than one largeconductive structure. Etching may be performed using a laser.

According to some embodiments (examples) of the invention, a method oftuning a resonance frequency of an etched planar antenna may comprise:scribing, rather than bulk removing, metal remaining within an interiorarea of the antenna so that there are a plurality of relatively smallisolated conductive structures rather than one large conductivestructure.

According to some embodiments (examples) of the invention, alaser-etched planar antenna may comprise: a conductive layer etched tohave a rectangular spiral pattern having a number of turns separated byspaces; and a plurality of small isolated conductive structures in theconductive layer in an interior area of the antenna.

According to some embodiments (examples) of the invention, a transponderchip module (TCM) may comprise: a conductive layer (CL) comprising acoupling frame (CF) having an inner edge (IE) defining an opening (OP),an outer edge (OE), and a slit (S) extending between the inner edge andthe outer edge; and may be characterized by: the conductive layerfurther comprising several small segments (428) of metal in an interiorarea of the coupling frame.

According to some embodiments (examples) of the invention, a method ofimproving the performance of a transponder chip module (TCM) having aconductive element selected from the group consisting of a couplingframe (CF) and planar antenna (PA), said conductive element formed froma layer (CL) of conductive material may comprise: forming an opening(OP) in the conductive layer by scribing, resulting in a large area ofresidual metal remaining within an interior area of the conductiveelement; and scribing the residual metal to have many segments, ofconductive material each of the segments having an area significantlysmaller than the area of the opening.

According to some embodiments (examples) of the invention, a method ofmaking a transponder chip module (TCM) may comprise: stamping a metalsheet (LF) to have a plurality of isolated conductive features (ICF, CP,C1-C8, CBR), at least some of which are contact pads (CP); andassembling a module tape (MT) having a planar antenna (PA) to thestamped metal sheet. A central opening (CO) may be provided the moduletape for mounting an RFID chip to a central area of the metal sheet.Through holes (TH) may be provided through the module tape for makingconnections to undersides of some of the isolated conductive features.The planar antenna may be formed by laser etching a conductive foil onthe module tape.

According to some embodiments (examples) of the invention, a method ofmaking contact side metallization for a transponder chip module maycomprise: stamping a metal sheet to have a pattern of ISO 7816 contactpads in an inner area thereof and additional isolated conductivefeatures in an outer area thereof.

According to some embodiments (examples) of the invention, contact sidemetallization (CSM) for a transponder chip module (TCM) may comprise:contact pads (CP, C1-C8, 1532) arranged in an inner area (1504) of thecontact side metallization; conductive features (1534) disposed in anouter area (1506) of the contact side metallization; and may becharacterized in that: the conductive features in the outer area areelectrically isolated from the contact pads in the inner area; and theconductive features in the outer area comprise at least 50% of the outerarea. The outer area may surround and may have approximately the samesurface area as the inner area. A transponder chip module (TCM) maycomprise such contact side metallization (CSM).

According to some embodiments (examples) of the invention, a method ofmaking at least one connection through a substrate may comprise:providing at least one through-hole (804) extending through thesubstrate; deforming a portion of a first conductive layer (CL1) whichspans the through-hole on one side of the substrate so that it extendsthrough the through-hole and at least to the opposite side of thesubstrate whereat it may contact and be joined with a second conductivelayer (CL2) on the opposite side of the substrate. The first conductivelayer (CL1) may be deformed with the second conductive layer disposed onthe substrate. The second conductive layer may be disposed on thesubstrate after the first conductive layer is deformed. Prior todeforming the portion of the first conductive layer, it may be cut orslit at the location of the through-hole, then bent to come into contactwith the conductive layer on the top, face-up side of the substrate.

In their various embodiments, the invention(s) described herein mayrelate to industrial and commercial industries, such RFID applications,payment smartcards, electronic passports, identity cards, access controlcards, wearable devices the like.

Other objects, features and advantages of the invention(s) disclosedherein, and their various embodiments, may become apparent in light ofthe descriptions of some exemplary embodiments that follows.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will be made in detail to embodiments of the disclosure,non-limiting examples of which may be illustrated in the accompanyingdrawing figures (FIGs). Some figures may be in the form of diagrams.Some elements in the figures may be exaggerated, others may be omitted,for illustrative clarity.

Any text (legends, notes, reference numerals and the like) appearing onthe drawings are incorporated by reference herein.

Some elements may be referred to with letters (“AM”, “BA”, “CB”, “CCM”,“CM”, “MA”, “MT”, “PA”, “TCM”, etc.) rather than or in addition tonumerals. Some similar (including substantially identical) elements invarious embodiments may be similarly numbered, with a given numeral suchas “310”, followed by different letters such as “A”, “B”, “C”, etc.(resulting in “310A”, “310B”, “310C”), and variations thereof, and maycollectively (all of them at once) referred to simply by the numeral(“310”).

FIG. 1 is a diagram (cross-sectional view) of a dual-interface smartcard (SC) and readers.

FIG. 1A is a diagram (plan view) showing the ISO-7816 specification forcontacts.

FIG. 1B is a diagram (plan view) of an exemplary 8-pad pattern forISO-7816 contacts.

FIG. 1C is a diagram (plan view) of an exemplary 6-pad pattern forISO-7816 contacts.

FIG. 1D is a diagram (plan view) of a smart card (SC).

FIG. 2 is a diagram (partial perspective view) of a module tape (MT) foran antenna module (AM) having a connection bridge (CBR).

FIG. 2A is a diagram (cross-sectional view) of a dual-interface antennamodule (AM) or transponder chip module (TCM).

FIG. 2B is a diagram (plan view) of a contact side of a dual-interfaceantenna module (AM) or transponder chip module (TCM).

FIG. 3A is a diagram (cross-sectional view) illustrating a couplingframe in a card body of a smart card.

FIG. 3B is a diagram (partial perspective view) illustrating a metalcard body modified to function as a coupling frame.

FIG. 4A is a diagram (plan view) illustrating a coupling frameincorporated into a transponder chip module.

FIG. 4B is a diagram (cross-sectional view) illustrating a couplingframe incorporated into a transponder chip module.

FIG. 4C is a diagram (partially cross-sectional view, partiallyperspective view, partially exploded view) illustrating a coupling frameincorporated into a transponder chip module.

FIG. 5A is a schematic diagram of an antenna module (AM) having anantenna and capacitive stubs.

FIG. 5B is a diagram (cross-sectional) view of the antenna module (AM)of FIG. 5A.

FIG. 5C is a diagram (plan view) showing a module tape (MT) having twoantenna structures, or module antenna segments (MA1, MA2).

FIG. 5D is a diagram (plan view) showing one possible way how the twoantenna segments MA1, MA12 of FIG. 5C may be connected with one another.

FIG. 5E is a diagram (plan view) of an antenna substrate.

FIG. 5F is a diagram (cross-sectional view) of the antenna substrate ofFIG. 5E, being mounted to a module tape (MT).

FIG. 5G is a diagram (cross-sectional view) of an antenna module havinga module antenna comprising two layers (MT1, MT2), each layer having anantenna coil (MA1, MA2).

FIG. 5H is a diagram (exploded cross-sectional) view of a transponderchip module having two module tapes (MT1, MT2).

FIG. 5I is a diagram (plan view) of a coupling frame doubling as aconnection bridge.

FIG. 5J is a diagram (plan view) of a coupling frame having a connectionbridge disposed in its slit (S).

FIG. 6 is a diagram (top view) of an array of contact pads (andconnection bridges) having conductive traces between the variousisolated conductive features of the contact side metallization (contactpads and connection bridges)

FIG. 7A is a diagram (plan view) of an antenna structure (AS) which maybe a module antenna (MA) in which a conductive layer (CL) which has beenetched to have tracks (traces) separated by spaces, with a large area ofthe conductive layer (CL) remaining within the antenna structure (AS).

FIGS. 7B, 7C, 7D are diagrams (plan view) of antenna structures (AS)which have been etched to have tracks (traces) separated by spaces, withsmaller, segmented areas of the conductive layer (CL) remaining within(in an inner area of) the antenna structure (AS).

FIGS. 8A, 8B, 8C are diagrams (cross-sectional views) illustrating anembodiment of a method of making connections through a substrate.

FIGS. 8D, 8E, 8F are diagrams (cross-sectional views) illustrating anembodiment of a method of making connections through a substrate.

FIG. 9 is a diagram (top view) showing leadframe (LF) having anarrangement of contact pads (CP; C1-C8) and connection bridges (CBR)which may be formed by a stamping process.

FIG. 9A is a diagram (exploded cross-sectional view) taken on a line A-Athrough FIG. 9, showing a leadframe (LF) being assembled to an antennasubstrate (AS).

FIG. 10A is a diagram (plan view) illustrating connecting a planarantenna having a conventional rectangular spiral geometry to an RFIDchip.

FIG. 10B is a diagram (plan view) illustrating connecting a planarantenna having a modified rectangular spiral geometry to an RFID chip. AU-shaped portion of the antenna allows an end of the antenna to becloser to the chip for making a wirebond connection.

FIGS. 11A-E are illustrations of a transponder chip module (TCM, orsimply “transponder module”) having a module tape (MT), contact pads andother isolated conductive features on a face-up side of the module tape,an RFID chip and a planar antenna which is in the form of a modifiedrectangular spiral (compare FIG. 10B) on the face-down side of themodule tape.

FIG. 12 is a reproduction of FIG. 2 of U.S. Pat. No. 8,100,337 (“SPS”).

FIG. 13 is a reproduction of FIG. 8 of US 20140152511 (“Gemalto”).

FIG. 14 is a diagram (plan view) of a transponder chip module havingconventional contact pads and connection bridges on the top (face-up)side of a module tape, and an RFID chip and a planar antenna on thebottom (face-down) side of the module tape.

FIGS. 15A and 15B are diagrams (plan views) of a transponder chip modulehaving contact pads in an inner area of and additional isolatedconductive features in an outer area of the top (face-up) side of amodule tape.

FIG. 15C is a diagram (in plan view) of a leadframe stamped to havevarious isolated conductive features such as contact pads in an innerarea and additional isolated conductive features in an outer area.

FIGS. 15D and 15E are diagrams (plan view) of different designs forcontact side metallization.

FIGS. 15F and 15G are diagrams (plan view) of different designs forcontact side metallization.

DETAILED DESCRIPTION

Various embodiments (or examples) may be described to illustrateteachings of the invention(s), and should be construed as illustrativerather than limiting. It should be understood that it is not intended tolimit the invention(s) to these particular embodiments. It should beunderstood that some individual features of various embodiments may becombined in different ways than shown, with one another. Referenceherein to “one embodiment”, “an embodiment”, or similar formulations,may mean that a particular feature, structure, operation, orcharacteristic described in connection with the embodiment is includedin at least one embodiment of the present invention. Some embodimentsmay not be explicitly designated as such (“an embodiment”).

The embodiments and aspects thereof may be described and illustrated inconjunction with systems, devices and methods which are meant to beexemplary and illustrative, not limiting in scope. Specificconfigurations and details may be set forth in order to provide anunderstanding of the invention(s). However, it should be apparent to oneskilled in the art that the invention(s) may be practiced without someof the specific details being presented herein. Furthermore, somewell-known steps or components may be described only generally, or evenomitted, for the sake of illustrative clarity. Elements referred to inthe singular (e.g., “a widget”) may be interpreted to include thepossibility of plural instances of the element (e.g., “at least onewidget”), unless explicitly otherwise stated (e.g., “one and only onewidget”).

In the following descriptions, some specific details may be set forth inorder to provide an understanding of the invention(s) disclosed herein.It should be apparent to those skilled in the art that theseinvention(s) may be practiced without these specific details. Anydimensions and materials or processes set forth herein should beconsidered to be approximate and exemplary, unless otherwise indicated.Headings (typically underlined) may be provided as an aid to the reader,and should not be construed as limiting.

Some processes may be presented and described in a series (sequence) ofsteps. It should be understood that the sequence of steps is exemplary,and that the steps may be performed in a different order than presented,some steps which are described may be omitted, and some additional stepsmay be omitted from the sequence and may be described elsewhere.

Reference may be made to disclosures of prior patents, publications andapplications. Some text and drawings from those sources may be presentedherein, but may be modified, edited or commented to blend more smoothlywith the disclosure of the present application.

In the main hereinafter, RFID cards, electronic tags and securedocuments in the form of pure contactless cards, dual interface cards,phone tags, electronic passports, national identity cards and electronicdriver licenses may be discussed as exemplary of various features andembodiments of the invention(s) disclosed herein. As will be evident,many features and embodiments may be applicable to (readily incorporatedin) other forms of smart cards, such as EMV payment cards, metalcomposite cards, metal hybrid cards, metal foil cards, access controlcards and secure credential documents. As used herein, any one of theterms “transponder”, “tag”, “smart card”, “data carrier”, “wearabledevice” and the like, may be interpreted to refer to any other of thedevices similar thereto which operate under ISO 14443 or similar RFIDstandard. The following standards are incorporated in their entirety byreference herein:

-   -   ISO/IEC 7810 is an ISO standard s an international standard that        defines the physical characteristics for identification cards.        The characteristics specified include: (i) physical        dimensions, (ii) resistance to bending, flame, chemicals,        temperature and humidity, and (iii) toxicity. The standard        includes test methods for resistance to heat.    -   ISO/IEC 14443 (Identification cards—Contactless integrated        circuit cards—Proximity cards) is an international standard that        defines proximity cards used for identification, and the        transmission protocols for communicating with it.    -   ISO/IEC 15693 is an ISO standard for vicinity cards, i.e. cards        which can be read from a greater distance as compared to        proximity cards.    -   ISO/IEC 7816 is an international standard related to electronic        identification cards with contacts, especially smart cards.    -   EMV standards define the interaction at the physical,        electrical, data and application levels between IC cards and IC        card processing devices for financial transactions. There are        standards based on ISO/IEC 7816 for contact cards, and standards        based on ISO/IEC 14443 for contactless cards.

A typical transponder chip module (TCM) described herein may comprise:

-   -   (i) a substrate, such as an epoxy-glass substrate, which may be        referred to as a module tape (MT) or a chip carrier tape (CCT)        and which may function as an inlay substrate;    -   (ii) an RFID chip (CM, IC) disposed on the substrate; and    -   (iii) a planar antenna (PA), or simply antenna structure (AS),        which may be a laser-etched antenna structure (LES) or a        chemically-etched antenna structure (CES) serving as a module        antenna (MA) for the transponder chip module (TCM).

When “chip module” is referred to herein, it should be taken to include“chip”, and vice versa, unless explicitly otherwise stated. When“transponder chip module” (TCM) is referred to herein, it should betaken to include “antenna module” (AM), and vice versa, unlessexplicitly otherwise stated. The transponder chip module (TCM) may alsobe referred to as a “transponder IC module”. Throughout the variousembodiments disclosed herein, unless specifically noted otherwise (inother words, unless excluded), the element referred to as “CM” will mostappropriately be a bare integrated circuit (IC) die (or RFID chip),rather than a chip module (a die with a carrier). Some figures maypresent examples that are specifically “chip modules” having IC chips(such as a “CM”) mounted and connected to substrates. A “chip module”(die and carrier) with a planar (etched) antenna structure (PA, AS, LES,CES) and connected thereto may be referred to as a transponder chipmodule (TCM).

Throughout the various embodiments disclosed herein, unless specificallynoted otherwise (in other words, unless excluded), the element referredto as “CM” will most appropriately be a bare integrated circuit (IC) die(or RFID chip), rather than a chip module (a die with a carrier). Somefigures may present examples that are specifically “chip modules” havingIC chips (such as a “CM”) mounted and connected to substrates. A “chipmodule” (die and carrier) with a planar (etched) antenna structure (PA,AS, LES, CES) and connected thereto may be referred to as a transponderchip module (TCM).

When “module tape” is referred to herein, it generally refers to amodule tape (MT) or chip carrier tape (CCT) comprising an epoxy-glasssubstrate having metallization (typically a copper layer) on one or bothsides thereof. The module tape (MT) may comprise insulating(electrically non-conductive) materials other than epoxy-glass, andprovides a substrate for supporting (and interconnecting) variouscomponents of the transponder chip module (TCM) with one another.

In some embodiments, the combination of a module tape (MT) and a moduleantenna (MA) may be referred to as an “antenna substrate” (AS). Themodule antenna (MA) may comprise an etched planar antenna (PA) in theform of a generally rectangular spiral having a having a number ofturns, comprising tracks (traces) separated by spaces. Some planarantennas may be formed by either chemical etching or laser etching(ablation). Generally, smaller track widths and smaller spaces betweentracks can be achieved with laser etching—for example, the planarantenna may have a track width of less than 100 μm, and a spacingbetween adjacent tracks of less than 75 μm.

When “module tape” is referred to herein, it generally refers to amodule tape (MT) or chip carrier tape (CCT) comprising an epoxy-glasssubstrate having metallization (typically a copper layer) on one or bothsides thereof. The module tape (MT, substrate) may comprise insulating(electrically non-conductive) materials other than epoxy-glass.

The module antenna (MA) may comprise two (or more) antenna structures,such as two antenna structures connected in series or parallel with oneanother, or one main antenna structure and capacitive stubs connected tothe ends of the antenna structure. A capacitor (CAP) may be connectedwith the module antenna (MA).

The transponder chip module (TCM) may comprise isolated metal (orconductive) features (or structures) such as contact pads (CP) andconnection bridges (CBR) on the top or face-up (contact) side of themodule tape (MT), and may also comprise an RFID chip (CM, IC) and aplanar (etched) antenna structure (AS, PA) on the bottom or face-down(chip or bond) side of the module tape (MT). Some components andfeatures on either side of the module tape (MT), such as the contactpads (CP), connection bridges (CBR) and antenna structure (AS) may belaser-etched or chemically-etched. Bond pads and interconnect traces mayalso be formed by etching on the bottom face-down side of the moduletape. An antenna incorporated directly on the RFID chip may inductivelycouple with the planar (etched) antenna structure (AS, PA) on theface-down (chip or bond) side of the module tape (MT). The isolatedmetal features (CP, CBR) on the face-up (contact) side of the moduletape (MT) may be formed by stamping a thin sheet (or layer, or foil) ofconductive material, such as copper, to have a pattern of isolated metalfeatures. The resulting stamped sheet may be referred to as a“leadframe” or as “contact side metallization” (CSM).

Contact side metallization (CSM) may also be referred to as a“faceplate” for the transponder chip module, and may be formed bystamping a metal sheet or by etching a conductive layer (CL) on asubstrate (typically, the module tape MT).

The term “layer” may be applied to any metal surface such as coppercladding or foil which may have a thickness of approximately 35 μm andwhich may be etched to form isolated conductive features (such ascontact pads) or a planar antenna. The term “layer” may also be appliedto a metal sheet which may have a thickness of approximately 70 μm andwhich may be stamped to form contact side metallization (such as contactpads and connection bridges). Some of these terms may be usedinterchangeably with one another. For example, the term “foil” may referto a sheet or a cladding, depending on the context.

Some of the descriptions that follow are in the context of dualinterface (DI, DIF) smart cards, but may relate mostly to thecontactless operation thereof. Many of the teachings set forth hereinmay be applicable to pure contactless cards, tags, wearables, securedocuments (e.g. electronic passports) and the like having only acontactless mode of operation. Some of the teachings set forth hereinmay be applicable to RFID devices, such as smart cards, which do nothave a booster antenna (BA).

When “inlay substrate” is referred to herein, it should be taken toinclude “card body”, and vice versa, as well as any other substrate fora secure document, unless explicitly otherwise stated or inapplicable tothe situation.

Generally, any dimensions set forth herein are approximate, andmaterials set forth herein are intended to be exemplary. Conventionalabbreviations such as “cm” for centimeter”, “mm” for millimeter, “μm”for micron, and “nm” for nanometer may be used.

FIG. 1 illustrates a smart card SC (100) in cross-section, along with acontact reader and a contactless reader. An antenna module (AM, ortransponder chip module TCM) 110 may comprise a module tape (MT) 112, anRFID chip (CM) 114 disposed on one side (face-down) of the module tapeMT along with a module antenna (MA) 116 and contact pads (CP) 118disposed on the other (face-up) side of the module tape (MT) forinterfacing with an external contact reader. The card body (CB) 120comprises a substrate which may have a recess (R) 122 extending into oneside thereof for receiving the antenna module (AM). (The recess R may bestepped—such as wider at the surface of the card body (CB)—toaccommodate the profile of the antenna module AM.) The booster antenna(BA) 130 may comprise turns (or traces) of wire (or other conductor)embedded in (or disposed on) the card body CB, and may comprise a numberof components such as (i) a card antenna (CA) component 132 and (ii) acoupler coil (CC) component 134. It may be noted that, as a result ofthe recess R being stepped, a portion of the card body (CB) may extendunder a portion of the antenna module (AM), more particularly under themodule antenna (MA).

FIG. 1A shows the ISO-7816 specification for a contact pad array (CPA).Eight contact pads C1-C8 are shown, The contact pads C1-C8 are locatedon the front surface of a smartcard. The dimensions are referenced tothe left and upper edges of the front surface of the card. For a 6-padlayout, the contact pads C4 and C8 may be omitted. The signalassignments for the contact pads are,

C1 VDD C2 RST_N C3 CLK C4 not used C5 VSS C6 not used C7 IO 1 C8 notused

The arrow in FIG. 1A (“insertion direction”) indicates the directionthat a smart card would be inserted into a reader, with contact pads C1,C2, C3 and C4 entering the reader first, followed by contact pads C5,C6, C7 and C8. (A 6 pad module does not have contact pads C4 and C8.)The “insertion direction” (or “card insertion direction”), as usedherein, may be defined as a direction parallel to a line drawn from C1to C5, or from C2 to C6, or from C3 to C7 or from C4 to C8. In ISO 7816,the minimum dimension for a contact pad may be 2 mm (in the insertiondirection)×1.7 mm in a direction perpendicular to the insertiondirection.

FIG. 1B is a diagram of an exemplary contact pad array (CPA) comprisingan 8-pad pattern for ISO 7816 contacts, and illustrates that an 8-padlayout may measure approximately 11.4 mm×12.6 mm.

FIG. 1C is a diagram of an exemplary contact pad array (CPA) comprisinga 6-pad pattern for ISO 7816 contacts, and illustrates that a 6-padlayout may measure approximately 8.0 mm×10.6 mm.

The rectangular border extending around the various contact pad arraysshown herein (around the contact pads and the connection bridges) mayrepresent the outer periphery of the underlying module tape (MT) as wellas a similarly sized opening (WO) in a card body (CB, or inlaysubstrate) for the transponder chip module (TCM).

-   -   In FIG. 1B, with a 0.2 mm space around the contact pad array        (CPA), the size of the opening (WO) may be approximately 11.8        mm×13.0 mm.    -   In FIG. 1C, with a 0.2 mm space around the contact pad array        (CPA), the size of the opening (WO) may be approximately 8.4        mm×11.0 mm.

As is evident from FIGS. 1A, 1B and 1C, there is a relatively largespace available in the center of the contact pad array (CPA) which maybe devoid of contact pads (CP). This area of the contact pad array(CPA), which may be referred to as the “central area”, may have the samecopper foil on it as that which is used to form the contact pads (CP),and the C5 (ground, earth) contact pad may be formed so as to extendinto the central area and be contiguous with metal in the central area.

FIG. 1D is a diagram showing conventional dimensions of a smart card(SC) having an ID-1 format, according to ISO/IEC 7810. The card body(CB) measures 53.98 mm×85.60 mm. A transponder chip module (TCM) isshown for insertion in the card body (CB). The transponder chip module(TCM) may be disposed in a window opening (WO) in the card body (CB).This figure illustrates the usual “form factor” for chip modules (inthis case, a transponder chip module TCM), and their location in thesmart card (SC).

Connection Bridges and Through-Hole Connections

US 20130146670 (2013; Grieshofer; “Infineon”) discloses a chip cardcontact array arrangement, comprising: a carrier; a plurality of contactarrays which are arranged on a first side of the carrier; anelectrically conductive structure which is arranged on a second side ofthe carrier, which is arranged opposite the first side of the carrier; afirst plated-through hole and a second plated-through hole; wherein thefirst plated-through hole is coupled to the electrically conductivestructure; a connecting structure which is arranged on the first side ofthe carrier, wherein the connecting structure connects the firstplated-through hole to the second plated-through hole; and theconnecting structure having a longitudinal extent which runs parallel toa direction in which a contact-connection device on a reading device ismoved relative to the plurality of contacts. See FIGS. 3, 4B and 4Cthereof. Infineon is specific regarding the use of plated-through holesto effect connections to the connecting structure having a longitudinalextent which runs parallel to a direction in which a contact-connectiondevice on a reading device is moved relative to the plurality ofcontacts.

FIG. 2 illustrates, generally, the concept of providing a connectionbridge (CBR) on the face-up (top, as viewed) side of the module tape(MT), for connecting (interconnecting) two components on the face-down(bottom, as viewed) side of the module tape (MT). The two components maybe a module antenna (MA) and an RFID Chip (CM, IC). Metallization on oneside (front; top, as viewed) of the module tape (MT) may be patterned tohave contact pads (CP, one shown) and a connection bridge (CBR, oneshown). For purposes of this discussion, the module tape (MT) may besingle-sided tape having metallization on only one side thereof, asillustrated. The concepts presented herein may also be applicable todouble-sided tapes having metallization on both sides thereof.

FIG. 2 shows a module antenna (MA) disposed around an RFID chip (CM,IC). The module antenna (MA) may have an outer end and an inner end, andthe outer end may need to “cross over” the module antenna (MA), fromoutside-to-inside, to connect with the RFID chip (CM, IC). (Thewire-wound module antenna shown in this figure is merely illustrative.The concepts disclosed herein are appropriate for etched, planarantennas (PA).) For purposes of this discussion, only one end of themodule antenna (MA), and connecting it with a component such as an RFIDchip is described.

In order to accomplish the “cross-over”, a connection bridge (CBR)extends between a first position (dot, “●”) above a first positionwithout (external to) the module antenna (MA) to a second position (“X”)above a second position within (internal to) the module antenna (MA). Afirst opening 20 may be provided through the module tape MT at the firstposition. A second opening 22 may be provided through the module tape MTat the second position.

The openings 20 and 22 may be referred to as “holes”, “blind holes”,“through holes” or the like, and, although they are used for makingconnections from one side of the module tape to the other, they aredifferent than “plated through holes”, since they are not plated.

FIG. 2 is generally illustrative of a transponder chip module (TCM) 200.An RFID chip (CM, IC) component is provided on the face-down (bottom, asviewed) side of the module tape (MT). A module antenna (MA) component isalso provided on the face-down side of the module tape (MT), on the sameside of the module tape (MT) as the RFID chip (CM, IC).

The module antenna (MA) in this example comprises a wire having two ends(only one end a is shown) and may be wound on a dam structure (DS, orwinding core WC). Generally, the two ends of the module antenna (MA) mayneed to be connected with corresponding two terminals “LA” and “LB”(only the “LA” terminal is shown in the figure) of the RFID chip (CM,IC). A module antenna (MA) wound on a dam structure is shown in FIGS. 3,3A, 4, 4A-4F of US 20140104133. It should be understood that an etchedplanar antenna may be used instead of a wire wound antenna. In the main,hereinafter, module antennas (MA) which are planar antennas (PA) arediscussed.

The dam structure (DS) may be located on the opposite side of the moduletape (MT) from the connection bridge (CBR), and may be aligned under theconnection bridge (CBR). The dam structure (DS) (or winding core WC) hasan interior portion (to the right, as viewed) and an exterior portion(to the left, as viewed). The module antenna (MA) is wound on theexterior of the dam structure (DS). The RFID chip (CM, IC) is disposedon the module tape (MT) in the interior of the dam structure (DS). Theillustrative end a of the module antenna (MA) extends external to themodule antenna (MA). In the event that both of two ends (only one shown)of the module antenna (MA) extend external to the module antenna (MA),two connection bridges may be needed to make connections such as toterminals of the RFID chip.

The connection bridge (CBR) extends between a first position (dot, “●”)above the a first position without (external to) the dam structure (DS)to a second position (“X”) above a position within (internal to) the damstructure (DS). A first opening 20 may be provided through the moduletape MT at the first position. A second opening 22 may be providedthrough the module tape MT at the second position.

The openings 20 and 22 through the module tape (MA) may be referred toas “blind holes” (or “blind vias”), and may have a diameter (or othercross-dimension) of approximately 300 μm-500 μm to facilitate wirebonding through the blind holes in the module tape (MT). Whenwire-bonding through the blind holes, is may be advantageous that theconductive layer (foil, cladding) of the contact pads (CP) andconnection bridge (CBR) have a thickness of approximately 35 μm, toavoid dents (dimpling). Alternatively, one connection to the connectionbridge (CBR) may be made using wire bonding, and another connection tothe connection bridge (CBR) may be made using plated-through holes (inthe manner of Infineon, which uses two plated-through holes).

-   -   A first portion 30 of the connection bridge (CBR) is disposed        over the first opening 20 A second end portion 32 of the        connection bridge (CBR) is disposed over the second opening 22.    -   A first end a of the module antenna (MA) may be wire-bonded,        through the first opening 20 to the underside of the first        portion 30 of the connection bridge (CBR), and that a first        terminal LA of the RFID chip (CM, IC) may be wire-bonded,        through the second opening 22 to the underside of the second        portion 32 of the connection bridge (CBR).        -   A planar antenna may have a connection pad at its outer end            which may be wire bonded through the first opening to an            outer portion 30 of the connection bridge.

The connection bridge (CBR) thereby provides a conductive path whichextends from a position which is above the exterior of the moduleantenna (MA) to a position which is above the interior of the moduleantenna (MA). This facilitates connecting a component (such as themodule antenna MA) which is disposed external to the dam structure (DS)to a component (such as the RFID chip CM) which is disposed internal tothe dam structure (DS). The connection bridge CBR facilitates making aninterconnect between an outer end of the module antenna (MA) componentand a terminal of the RFID chip (CM, IC) component. An outer end of anetched, planar antenna (PA) may be connected by a wirebond throughopening 20 in the module tape (MT) to an outer position on the undersideof the connection bridge (CBR), and a terminal of the RFID chip (CM) maybe connected through the opening 22 to an inner position on theunderside of the connection bridge (CBR).

Although some of the antenna structures and module antennas describedherein may be disclosed as being wire-wound, there may be someapplicability of the concepts disclosed in conjunction therewith to theetched, planar antennas (PA) described herein.

FIG. 2A shows an antenna module (AM) or transponder chip module (TCM)comprising contact pads (CP) disposed on one side (or surface; top, asviewed) of a module tape (MT, or substrate) and a planar antenna (PA, ormodule antenna MA) and an RFID chip (CM, IC) disposed on the oppositeside (or surface; bottom, as viewed) of the module tape (MT). The planarantenna (PA) is disposed around the RFID chip (CM, IC). The planarantenna (PA) has two ends—an inner end disposed interior to the planarantenna (PA) (towards the RFID chip), and an outer end disposed exteriorto the planar antenna (PA). The inner end of the planar antenna (PA) maybe connected directly (or via interconnect traces on the face-down sideof the module tape (MT)) to a terminal (such as “LA”) of the RFID chip(IC, CM). However, the other, outer end of the planar antenna (PA) must“cross over” the planar antenna (PA) in order to be connected with asecond terminal (such as “LB”) the RFID chip (IC, CM). This can be donewith interconnect traces on the face down (bottom, as viewed) side ofthe module tape (MT). Alternatively, as will be seen in subsequentfigures the outer end of the planar antenna (PA) structure mayconnected, through the module tape (MT) to an outer end of a connectionbridge (CBR) disposed on the face up (top, as viewed) side of the moduletape (MT), the connection bridge (CBR) can extend to a positioncorresponding to the interior of the planar antenna (PA) structure, anda connection can be made from the inner end of the connection bridge(CBR), through the module tape (MT) to a second terminal of the RFIDchip (IC, CM).

In contrast with the planar antenna (PA), which may have one endoriented towards its interior and one end oriented towards its exterior,a wire wound module antenna (MA, or antenna structure AS) may have (i)both of its ends oriented towards the interior of the antenna structure(AS), (ii) one end oriented towards the interior and one end orientedtowards the exterior of the antenna structure (AS), or (iii) both of itsends oriented towards the exterior of the antenna structure (AS). Ifboth ends of an antenna structure (AS) are oriented towards the exteriorof the antenna structure (AS), two connection bridges may be required toeffect connections to the RFID chip (CM, IC).

FIG. 2B shows an antenna module (AM) or transponder chip module (TCM)200 having a contact pad array (CPA) 202 comprising of 8 contact pads(C1-C8). The transponder chip module (TCM) also has two connectionbridges (CBR-1, CBR-2) 210, 212 on its contact (face-up) side of themodule tape (MT, not shown). An RFID chip (CM, IC, not shown) and amodule antenna (MA, shown in dashed lines) may be disposed on theface-down side (not visible) of the module tape (MT). A border is shownaround the transponder chip module (TCM), which may represent an opening(WO) in a card body (CB, or inlay substrate) for the transponder chipmodule (TCM).

The connection bridges (CBR-1, CBR-2) and contact pads (C1-C8) may beformed from a common conductive layer or foil of copper (for example),such as on a single-sided module tape (MT) which may have a conductivelayer (or foil) on its face-up side having a thickness of 35 μm. Themodule tape (MT) may also be double-sided, having conductive layers(foils) on both its face-up and face-down sides. Having two connectionbridges (CBR-1, CBR-2) may be useful in circumstances (i) when there aretwo module antennas (MA-1, MA-2), or (ii) when there is a single moduleantenna (MA) with a center-tap, or (iii) when there is a single moduleantenna (MA) with both of its ends oriented outward.

The module antenna (MA) may be a planar antenna (PA) which may be anetched (chemical or laser) antenna structure (AS). Alternatively, themodule antenna (MA) may be a non-planar, wire-wound antenna structure(AS). FIG. 2 shows an example of a module antenna (MA) comprising wirewound on a dam structure (DS).

The connection bridge (CBR-1) 210 is shown disposed above the C1 contactpad, is generally “L-shaped”, and extends from an outer position(indicated by a round dot “●”) which is without (external to) thecontact pad array (CPA) and without (external to) the module antenna(MA) to an inner position (indicated by an “X”) which is within(internal to) the contact pad array (CPA) and within (internal to) themodule antenna (MA). Connections of components on the underside (facedown side) of the module tape (MT) may be made to the connection bridge(CBR-1) to achieve interconnects (such as illustrated in FIG. 2A) whichmay otherwise require troublesome cross-overs or additional interconnectlayers. Notably, in this illustration, an outer end of the moduleantenna (MA) on the underside of the module tape (MT) may be connectedto the outer position (“●”) of the connection bridge CBR-1, and aterminal of the RFID chip (not shown, see FIG. 2A) may be connected tothe inner position (“X”) of the connection bridge CBR-1.

The second connection bridge (CBR-2) 212 is shown disposed above the C5contact pad, and may be substantially a mirror image of the connectionbridge (CBR-1), may be used to effect other or additional connections(not shown or described), and will not be described further. Having twoconnection bridges is optional. In cases where only one connectionbridge is needed, the connection bridge (CBR-2) may suffice. Either orboth of the connection bridges (CBR-1, CBR-2) may be positioned belowthe contact pad array (CPA) rather than above it.

In the illustration of FIG. 2B, the bottom contact pads C4 and C8(otherwise, the bottom contact pads C3 and C7, for a 6 pad array) may beshaped to resemble the connection bridges pads (CBR-1, CBR-2), foraesthetic purposes. Also, as shown herein, the contact pads C2 and C6may be “T-shaped”, and the neighboring contact pads C1/C3 and C5/C7 mayhave cutouts to accommodate the top of the “T”, as shown, also foraesthetic purpose.

Laser-etched Antenna Structures (LES)

U.S. Ser. No. 14/281,876 filed 19 May 2014 (US 20140284386 published 25Sep. 2014) discloses LASER ABLATING STRUCTURES FOR ANTENNA MODULES FORDUAL INTERFACE SMARTCARDS. Laser etching antenna structures for RFIDantenna modules (AM) and combining laser etching and chemical etchingare disclosed. Limiting the thickness of the contact pads (CP) to lessthan the skin depth (18 μm) of the conductive material (copper) used forthe contact pads (CP). Multiple antenna structures (AS1, AS2) in anantenna module (AM), and incorporating LEDs into the antenna module (AM)or smartcard (SC) are also disclosed.

Generally, the transponder chip modules (TCM) disclosed herein may havea conductive (typically copper) layer for forming a planar moduleantenna (MA, PA) which may have a thickness greater than or almost equalto the skin depth of copper (˜18 μm), for example 18 μm-35 μm, but itcould also be 12 μm. The module antenna (MA) may be directly underneaththe contact pads (CP) or connection bridges (CBR).

Generally, in practice, the thickness of metal cladding (metal layer ML,conductive layer CL) on one or both sides of a single-sided ordouble-sided module tape (MT), respectively, which may be laser-etchedto form contact pads (CP) on the face-up side of the module tape (MT), aplanar antenna (PA) on the face-down side of the module tape (MT), and acoupling frame (CP) on either side of the module tape (MT) is not lessthan 18 μm. A coupling frame (CF), described herein below, should have athickness greater than the electromagnetic transparency of the metallayer in question. In the case of single- or double-sided copper-cladmodule tape (MT), the metal layer typically has a thickness of 18 μm or35 μm.

Laser etching is a form a laser ablation where material may be removedfrom a typically planar sheet (or foil) of material, and has someadvantages over conventional wet etching (chemical etching). A laseretch can proceed more uniformly through the material being etched, andcan also be controlled such as by increasing or decreasing the laserpower and subsequent etching at various portions of a pattern beingetched, in a highly-controllable manner. (With conventional wet/chemicaletching, the width of the etch may be tapered, narrowing from thesurface of the material being etched to the bottom of the etchedfeature. In contrast therewith, with laser etching, straight walletching can be achieved whereby the sides of the feature being etchedmay be substantially parallel with one another.)

Using laser etching, the spaces between tracks of an antenna structure(AS, MA, PA) may be dimensionally equal to the width (kerf) of the laserbeam, such as approximately 25 μm. The tracks themselves may have awidth of 25 μm-100 μm. If a coupling frame (CF) is formed from the samemetal layer (ML) as the planar antenna (PA), a gap (space) between theouter track of the planar antenna (PA) and an inner edge (IE) of thecoupling frame (CF) may also be equal to the width (kerf) of the laserbeam, such as approximately 25 μm. After plating, the dimension of thespaces/gap may be smaller, by a few microns, such as 20 μm.

The antenna (or antenna structure AS) may be laser etched from a copperlayer (cladding or foil), which may have a thickness less than the skindepth of copper (˜18 μm), forming a number of tracks separated by adistance approximately equal to the width (or kerf) of the laser beam,such as approximately 25 μm. Subsequent to laser etching, the antennastructure may be plated, which may reduce the distance between tracks toapproximately 20 μm (for example). This may result in increasedperformance of the antenna structure, and the overall antenna module AM(or transponder chip module (TCM)), and reduce performance constraintson the performance of a booster antenna (BA) in the card body (CB) ofthe smartcard (SC). The track width may be less than 100 μm, and thespacing between tracks may be less than 50 μm.

The antenna structure (AS) may be formed by laser etching, having anumber of (such as 10 or 12) tracks which are disposed substantiallyplanar with one another on a module tape (MT) or other suitablesubstrate, in a generally rectangular spiral pattern. The spacingbetween tracks may be on the order of 25 μm, or less (such as 20 μm,after plating).

As described in U.S. Ser. No. 14/465,815 filed 21 Aug. 2014, (US20140361086, published 11 Dec. 2014) the track width on the laser-etchedantenna structure (LES) can be varied, from end-to-end, to improveperformance, in contrast with an antenna structure having a single(constant) track width. By way of analogy, this could be viewed as morethan one antenna, each having a different track width, connected inseries with one another. As an example, a first portion of an antennastructure may have a track width of 100 μm, another portion may have atrack width of 50 μm. Additional portions may have other track widths.The spacing between tracks may also be varied. For example, the spacingbetween some tracks may be 25 μm or less, the spacing between some othertracks may be more than 25 μm. The ability to vary track width andspacing may be helpful in fine-tuning the performance of the module,with attendant benefits in activation distance (for example).

Coupling Frames

As used herein, a “coupling frame” (CF) may be a planar conductivestructure surrounding (disposed around) and closely adjacent to(including overlapping) a module antenna (MA) of a transponder chipmodule (TCM). The coupling frame (CF) has an inner edge defining anopening, an outer edge, and a slit (or slot, or gap) extending betweenthe opening (or inner edge) and the outer edge.

U.S. Ser. No. 14/465,815 filed 21 Aug. 2014 (US 20140361086 published 11Dec. 2014) discloses that a smartcard (SC) may comprise anelectrically-conductive layer, referred to herein as a “coupling frame”(CF) disposed in the card body (CB) around at least two sides (or 180°)of a transponder chip module (TCM) so as to be in close proximity (oroverlapping) with the module antenna (MA) in the transponder chip module(TCM). The coupling frame (CF) may nearly completely surround thetransponder chip module (TCM), such as all four sides (or 360°) thereof,minus a slit (S). The slit (S) may be very small, such as 50 μm. Acoupling frame (CF), at least partially surrounding a transponder chipmodule (TCM) and residing substantially on the same plane as thelaser-etched antenna structure (LES) in a card body, document or tag,without creating a closed circuit around the transponder chip module(TCM) by leaving at least one space or gap as an open circuit such as acut-out, slit or slot in the coupling frame (CF), may increase theamplitude of the resonance curve of the transponder chip module (TCM)with minimal frequency shift when interrogated by a reader, and mayincrease the activation distance. See also U.S. Ser. No. 14/492,113filed 22 Sep. 2014 (US 20150021403 published 22 Jan. 2015).

FIG. 3A shows an example of a smartcard (SC) 300 with a coupling frame(CF) 320 incorporated into its card body (CB) 302 which has a steppedrecess (R). A transponder chip module (TCM) 310 has a planar antenna(PA) which may be a laser-etched antenna structure (LES) 312. Thecoupling frame (CF) has an opening (MO) 308 for receiving thetransponder chip module (TCM) 310. The dashed line indicates,schematically, either a metal layer in a stackup of a card body, or asubstantially entirely metal card body (CB). When “metal layer” isreferred to herein, it may refer to such a metal card body. An inneredge of the coupling frame (CF) may overlap some outer turns of thelaser-etched antenna structure (LES) in the transponder chip module(TCM). Viewed from another perspective, an outer portion of the planarantenna (PA) may overhang an inner portion of the coupling frame (CF).

FIG. 3B shows a transponder chip module (TCM) 310 disposed in the cardbody (CB) 302 m of a metal smartcard (SC) 300 m, or metal card (MC),wherein substantially the entire card body (e.g., 760 μm thick)comprises metal, and may be referred to as a metal card body (MCB). Forsuch a metal card (MC), there has to be a non-conductive area behind thetransponder chip module (TCM). The transponder chip module (TCM) residesin an opening (MO) 308, in the metal card body (MCB) 302 which may alsobe referred to as a module opening (MO). The opening (MO), may beprepared by mechanical milling, or laser ablation, and may be at leastthe size of the laser etched antenna structure (LES) 312, and may bestepped (for an example of a stepped recess/opening, see FIG. 3A) sothat a portion of the metal card body (MCB) overlaps (underneath, asviewed) an outer portion of the laser-etched antenna structure (LES).

Throughout the embodiments disclosed herein, antenna structures (AS)which are other than laser-etched may be substituted for thelaser-etched antenna structure (LES), if they can be made to exhibitsufficient performance, such as by having appropriate track width andspacing between tracks. These parameters are discussed elsewhere in thisdocument.

For a metal card (MC), the back (bottom, as viewed) of the metal cardbody (MCB) should be open (free of metal, non-conductive) to avoidattenuation of the electromagnetic field. In other words, the opening(CO, or MO) should extend completely through the card body. This leavesa void 303 behind (below, as viewed) the transponder chip module (TCM)which may be filled with an epoxy or resin (“filler”) 304. The void canbe filled with a resin or with an active synthetic material (“filler”)which illuminates during an electronic transaction (e.g., whilst beinginterrogated by an external reader). The void beneath the transponderchip module (TCM) could be a series of perforations, a slit or annulusthat permits communication of the transponder chip module with thereader.

A slit (or slot, or gap, or band) (S) 330 may be provided through themetal card body (MCB) so that it can function as a coupling frame (CF)for capacitive coupling with a contactless reader.

A card body (CB) with a coupling frame (CF), or a metal card body (MCB)modified (such as with a slit) to act as a coupling frame (CF) may beprovided as an interim product, into which a transponder chip module(TCM) may later be installed.

U.S. Ser. No. 14/551,376 filed 24 Nov. 2014, discloses a coupling frame(CF) may be incorporated into an antenna module (AM) or transponder chipmodule (TCM), and may be formed from the same conductive layer (CL) asthe contact pads (CP) on the face-up side of the module tape (MT).Alternatively, the coupling frame (CF) (or additionally, a secondcoupling frame) may be formed from the same conductive layer (CL) as amodule antenna (MA), such as an etched planar antenna (PA), on theface-down side of the module tape (MT). Such a transponder chip module(TCM) with a coupling frame (CF) integrated therewith may be referred toherein as a “capacitive coupling enhanced” (CCE) transponder chip module(TCM).

The coupling frame (CF) may be in the form of a ring (such as arectangular ring) having an opening (OP), an inner edge (IE) whichdefines the opening, and an outer edge (OE). A discontinuity which maybe a slit (S) or a non-conductive stripe (NCS) may extend from the inneredge (IE) or opening (OP) to the outer edge (OE) so that the ring of thecoupling frame (CF) is an open loop (discontinuous) conductor having twoends and a gap (which is the slit) there between.

The coupling frame (CF) may be disposed with its inner edge (IE) closelyadjacent to and partially surrounding the module antenna (MA) of atransponder chip module (TCM), and may be substantially coplanar withthe module antenna (MA). The coupling frame (CF) may surround at leasttwo sides of the planar antenna (PA) structure, such as three sidesthereof, or all four sides (except for the slit). When the term“partially surrounding” is used herein, it generally may refer to such acoupling frame (CF) which substantially surrounds (except for the slit,slot or gap) the module antenna (MA) of the transponder chip module(TCM). The coupling frame (CF) comprises a suitableelectrically-conductive material capable of interacting with RF from themodule antenna (MA) and an external RFID reader, enhancing couplingbetween the transponder chip module (TCM) and the external reader.

Some embodiments of capacitive-coupling enhanced (CCE) transponder chipmodules (TCM) will now be described, and may utilize any of the conceptsdescribed above. These transponder chip modules (TCM) may operate solelyin a contactless mode, rather than being dual interface modules havingcontact pads.

FIGS. 4A and 4B are diagrams showing a capacitive coupling enhancedcapacitive-coupling enhanced transponder chip module (CCE-TCM, 400)comprising:

-   -   a module tape (MT, 402);    -   an RFID chip (IC, 408) disposed on the module tape (MT);    -   an etched planar antenna (PA, 420) or module antenna (MA)        disposed on the module tape (MT); and    -   a coupling frame (CF, 424) disposed on the module tape (MT),        closely adjacent to the module antenna (MA), having an inner        edge 423 defining an opening (OP) 405 aligned (such as        concentric) with the planar antenna (PA) and a slit (S, 426)        extending from the inner edge 423 or opening (OP) to an outer        edge (OE) 425 of the coupling frame (CF) so that the coupling        frame (CF) is an open loop. There may be a small gap between the        inner edge (IE) of the coupling frame (CF) and an outer turn of        the planar antenna (PA).

In FIG. 4B, the RFID chip (IC) is shown on the same side of the moduletape (MT) as the planar antenna (PA) which, may be either the face-up orface-down side of the module tape (MT). In this contactless-only, singleinterface embodiment, it is ambiguous which side is face-up and whichside is face-down, since there are no contact pads (CP) defining whichis the face-up side. Nevertheless, the concept of an electrically “openloop” coupling frame (CF) disposed closely adjacent to and surroundingthe module antenna (MA)—whether the coupling frame (CF) is on the sameor on an opposite side of the module tape (MT) as/from the moduleantenna (MA)—may be applied to dual-interface (DI) transponder chipmodules (TCM) also having contact pads (CP) for a contact interface, asshown in many of the examples presented herein.

By incorporating in or adding an open-loop coupling frame (CF) to thetransponder chip module (TCM), coupling between the resulting capacitivecoupling enhanced-transponder chip module (CCE-TCM) and an externalreader (FIG. 1; “contactless reader”) may be improved, includingincreasing activation distance and read/write distance. The improvementmay be sufficient that the capacitive coupling enhanced-transponder chipmodule (CCE-TCM) may operate independently, without requiring a boosterantenna (BA) or the like which are found in smart cards. The capacitivecoupling enhanced-transponder chip module (CCE-TCM) may have a largerform factor than a conventional transponder chip module (TCM), and maybe incorporated into RFID devices other than smart cards, such aswristband devices (discussed hereinbelow), key fobs, devices with USB(universal serial bus) interfaces, and the like, having various formfactors.

FIG. 4C shows another example of an integrated coupling frame (ICF)transponder chip module (TCM) 400 having a coupling frame (CF) 424integrated therewith on the module tape (MT) 402. The coupling frame CDmay be formed by laser etching a conductive layer (CL) 404 on the moduletape MT. has an opening (OP) 405 defined by an inner edge (IE) 423, anouter edge (OE) 425, may be disposed on a top (as viewed) surface of themodule tape, and may be provided with a slit (S) 426 extending from theinner edge (IE) to the outer edge (OE). A planar antenna (PA) 420 may bedisposed on the bottom (as viewed) of the module tape. In this example,the transponder chip module may operate purely contactlessly(contactless interface only), without contact pads (no contactinterface).

A double-sided module tape (MT) has a top surface with copper cladding(a layer of metal) and a bottom surface with copper cladding (a layer ofmetal). The copper layers may be approximately 35 μm thick.

The copper cladding on the top surface of the module tape may belaser-etched to be in the form of a coupling frame (CF) having an inneredge (IE) defining an inner area, an outer edge (OE), and a slit (S)extending between the inner edge and the outer edge.

Metal (copper cladding, conductive layer CL) remaining within the inner(interior) area of the coupling frame (CF) may be segmented (such as bylaser etching or scribing) into several small areas or segments 428 ofmetal. For example, the inner area may measure approximately 9 mm×9 mm.Each segmented area of metal in the inner area may measure less thanapproximately 2 mm×2 mm, such as approximately 1 mm×1 mm, or evensmaller (such as approximately 200 μm×200 μm). Only some of thesegmented areas are shown, for illustrative clarity. Segmenting versusbulk removal of metal is discussed with respect to FIG. 7A-D, in thecontext of metal remaining in an inner area of a planar antenna. Metal(not shown) remaining outside the area of the coupling frame, if any,may or may not be segmented, or may be entirely removed.

The copper cladding on the bottom surface of the module tape may belaser-etched to form a planar antenna (PA) having a number of turns,such as 10 turns, arranged in a rectangular spiral pattern in a path (orband) extending around a central area of the module tape. The overallwidth of the antenna may be approximately 10 mm, and the antenna may bedisposed so as to be at least partially, including completely under thecoupling frame. In the figure, the antenna is shown disposed entirelyunder an inner portion of the coupling frame.

Metal (copper cladding) remaining within the inner area of the planarantenna may be segmented (such as by laser etching or scribing) intoseveral small areas (segments) of metal, in the manner discussed withrespect to FIGS. 7B-D. For example, the inner area may measureapproximately 9 mm×9 mm. Each segmented area of metal in the inner areamay measure less than approximately 2 mm×2 mm, such as approximately 1mm×1 mm, or even smaller (such as approximately 200 μm×200 μm). Metalremaining outside the area of the planar antenna, if any, may or may notbe segmented, or may be entirely removed.

An RFID chip (IC) 404 may be disposed on the bottom side of the moduletape in the segmented inner area of the antenna. All of the metal underthe RFID chip may be removed, leaving only some of the segmented metal,so that the RFID chip may be mounted directly to the module tape (MT).Alternatively, the RFID chip may be disposed on the top side of themodule tape, but that would require some making some kind of connectionsbetween the antenna on the bottom side of the module tape and the RFIDchip on the top side of the module tape.

The planar antenna (PA) is shown located under an inner portion of thecoupling frame. It may be beneficial that the coupling frame cover(overlap) at least 90% of the antenna. The antenna may be locatedanywhere on the bottom surface of the module tape, so that is overlappedby the coupling frame, such as under an outer portion of the couplingframe, but for connecting with the RFID chip it may be generally betterthat the antenna be disposed, as shown, close to the RFID chip.

The resulting transponder chip module (TCM) with integrated couplingframe may have a form factor larger than the typical transponder chipmodule.

Antenna Substrates and Multiple Antenna Structures

FIG. 5A is a schematic diagram and FIG. 5B is a cross-sectional view ofan antenna module 200. The antenna module 200 comprises an RFID chip CM208, an antenna structure “A” 210 having two ends (1,2), an antennastructure “B” 212 having two ends (3,4) and an antenna structure “C”having two ends (5,6). The antenna structures A,B,C are connected asshown, with the ends “3” and “6” being free ends. The antenna structuresB and C may be considered to be capacitive stubs. A more completedescription of this may be found in U.S. Pat. No. 8,474,726.

FIG. 5C is a diagram showing a module tape (MT) having two antennastructures, or module antenna segments (MA1, MA2). The two moduleantenna segments MA1, MA2 may be arranged concentric with one another,as inner and outer antenna structures. Both module antenna segments MA1,MA2 may be wound coils, or patterned tracks, or one may be a wound coiland the other a pattern of tracks. The two module antenna segments MA1,MA2 may be interconnected with one another in any suitable manner toachieve an effective result. For example, the two module antennasegments MA1, MA2 may be connected in any suitable manner with oneanother. The antenna segments (MA1, MA2) may be considered to be twoantenna structures (AS1, AS2).

FIG. 5D is a diagram showing one possible way how the two antennasegments MA1, MA2 of FIG. 5C may be connected with one another. Hereinthe two antenna segments are referred to as inner segment IS and outersegment OS, and the antenna structure comprises

-   -   an outer segment OS having an outer end 7 and an inner end 8    -   an inner segment IS having an outer end 9 and an inner end 10    -   the outer end 7 of the outer segment OS is connected with the        inner end 10 of the inner segment IS    -   the inner end 8 of the outer segment OS and the outer end 9 of        the inner segment IS are left unconnected    -   this forms what may be referred to as a “quasi dipole” antenna        structure AS.        -   Such an arrangement is shown and described in U.S. Pat. No.            8,474,726 for use as a booster antenna BA in the card body            CB of a smartcard SC        -   Such an arrangement is shown and described in U.S. Pat. No.            8,366,009 for use as a booster antenna BA in the card body            CB of a smartcard SC

FIGS. 5E, 5F illustrate that the antenna MA may be formed on an antennasubstrate AST which may be substantially the same size as and separatefrom a module substrate (or tape) MT. The antenna substrate may comprisean insulating material or film (or tape), such as Kapton or PET(polyethylene terephthalate). An opening OP in the antenna substrateAST, which may be only slightly larger than the chip CM, may be providedthrough the antenna substrate AS for accommodating the chip CM (the chipCM may protrude through the opening OP) when the antenna substrate ASTis joined (and connected) to the module substrate MT. In FIG. 5E, thechip CM and its interconnections are shown in dashed lines. As bestviewed in FIG. 5F, the antenna substrate AST may be and may have bumpson its bottom (as viewed) surface which will be connected withcorresponding pads on the top (as viewed) surface of the modulesubstrate MT, such as by using a conductive adhesive. By avoiding theproblem of leaving the area around the chip CM free for interconnects,this area can be used for additional turns (or tracks) of the antennaMA. Some of these additional tracks are shown in dashed lines in FIG.5E. The antenna substrate AST may be opaque, or dark in color to concealthe underling module substrate MT, chip CM and antenna MA. This may bean important security feature if the module substrate MT is transparent(such as the PET substrate used by Parlex).

The antenna MA may be formed of wire, embedded in the antenna substrateAS, such as shown in U.S. Pat. No. 6,233,818. Alternatively, the antennaMA may be chemically etched from a metal layer (foil) on the antennasubstrate AST. Alternatively, the antenna MA may be laser etched, whichmay allow for finer pitch, and more tracks. For example, the antenna maybe laser etched (isolation technique) into a copper cladded “seed” layer(face-down side of the pre-preg) having a thickness of 18 μm, using a UVor Green nanosecond or picosecond laser with a distance between tracksdimensionally equal to the width (kerf) of the laser beam, approximately25 μm. After the laser etching of the copper seed layer, the antennasubstrate AS may further be processed by one or more of sand blasting toremove residual laser ablated particles and to prepare for platingadhesion; depositing carbon to support the through-hole plating of thevertical interconnects; dry film application and photo-masking process;electroless deposition copper (Cu˜6 μm) to increase the thickness of thetracks; electro-plating of nickel and nickel phosphorous (Ni/NiP˜9 μm)or nickel (Ni˜9 μm) and palladium/gold or gold (Pd/Au or Au—0.1 μm/0.03μm or 0.2 μm) to prevent oxidization.

FIG. 5G shows an antenna module AM comprising two module tape layers MT1and MT2, each layer having an antenna coil MA1 and MA2, respectively.The antenna module AM may comprise two layers of an insulating materialsuch as PET or copper clad epoxy glass, each having an antenna withapproximately 12 turns. The layers may each be considered to be moduletapes MT, and may each be considered to be an antenna substrate AST. Afirst one of the layers (the bottom layer in the figure) MT1 may bedouble-sided, having a first antenna structure (or coil) MA1 formed ordisposed on one side thereof and a contact interface with contact padsCP on the other side thereof. A second one of the layers (the top layerin the figure) MT2 may have an second antenna structure (or coil) MA2formed on one side thereof, and an opening for receiving and positioninga chip, which may be a flip chip. The two antenna coils (MA1, MA2) maybe considered to be two antenna structures (AS1, AS2), and may be formedby tracks of conductive material (such as copper) separated by spaces.

The RFID chip CM may be connected to pads associated with interconnecttraces and vias on the first (bottom) layer MT1. The first and secondantenna structures MA1, MA2 may be interconnected to form the moduleantenna MA, such as in series with one another, and may be connected tothe chip CM. A resulting dual interface (DIF) module may have six (6)contact pads CP, and may measure approximately 10.6 mm×8.0 mm (see FIG.1C).

FIG. 5H shows an embodiment of a transponder chip module (TCM) 500comprising two module tapes (MT1, MT2). The module tapes are exemplaryof any substrate having two opposite sides or surfaces. The two moduletapes may be joined together, as shown (broken line).

A first module tape (MT1) or antenna substrate (AS) 502 may besingle-sided copper clad, such as glass epoxy having a thickness ofapproximately 70 μm with a conductive (such as copper) layer (CL) 504 onthe bottom side or surface (as viewed) thereof. The copper layer mayhave a thickness of approximately 18 μm. The copper layer CL may bepatterned (such as by laser etching) to have (to be in the form of) anantenna structure (AS) or module antenna (MA) which may be a planarantenna (PA) 506 having a number (such as approximately 10 or 11) ofturns. The planar antenna (PA) or antenna structure (AS), which servesas a module antenna (MA) may be chemical (wet) etched or laser etched.

A second module tape (MT2) 522 which may be double-sided copper clad,such as glass epoxy having a thickness of approximately 70 μm with aconductive (such as copper) layer (CL1) 524 on the top (as viewed) sideor surface thereof and a conductive (such as copper) layer (CL2) 526 onthe bottom (as viewed) layer thereof. The copper layers CL1 and CL2 mayboth be approximately 35 μm thick. The copper layer CL1 may be patterned(such as by laser etching) to have contact pads (CP) 528. The copperlayer CL2 may be patterned (such as by laser etching) to have aconnection bridge (CBR) 530 and also to have bond pads (not shown).Plated through holes (PTH) 532, as an example of any conductive element,may be provided (extending) through the module tape MT2, aligned with(and in contact with) at least some of the contact pads CP, to allow formaking connections from an RFID chip (IC) 508 to the contact pads CP.

Although shown on only one side (left, as viewed) of the module tapeMT2, the connection bridge may extend around an outer area of the moduletape MT2 in the manner of a coupling frame having a slit, such has beendiscussed hereinabove. (A coupling frame CF functioning as a connectionbridge CBR is disclosed in U.S. Ser. No. 14/551,376, at FIG. 3Bthereof.) Although not shown, a coupling frame may be incorporated onthe top (as viewed) side of the module tape MT1.

FIG. 5I shows the conductive layer (CL2) 526 patterned to have acoupling frame (CF) 550 having a slit (S) 552. A portion 554 of thecoupling frame may serve as a connection bridge, making a connectionfrom an outer portion (indicated by the dot “●”), to an inner portion(indicated by the “x”) thereof, such as was discussed with respect toFIGS. 2 and 2B.

FIG. 5J shows that the conductive layer (CL2) 526 may be patterned tohave a coupling frame (CF) 550 with a slit (S) 552 which is wide enough(such as approximately 500 μm-1 mm wide) to accommodate a connectionbridge (CBR) 556 in the slit. The coupling frame may extend beyond theboundaries of the contact pads 528 and the antenna 506 (such as shown inFIG. 5H).

An opening (OP) 510 extending through the module tape MT1 allowsplacement (mounting) of the RFID chip (IC) 508 onto a second module tape(MT2).

A number of through holes (TH) may be provided (extending) through themodule tape (or antenna substrate) MT1 to allow for wire bonds to bemade to the connection bridge CBR and the plated through holes PTH. Athrough hole 542 is aligned with an outer portion of the connectionbridge, and a wire bond connection wb1 may be made through the throughhole 542 from an outer end of the antenna to the outer portion of theconnection bridge. A through hole 544 is aligned with an inner portionof the connection bridge, and a wire bond connection wb2 may be madethrough the through hole 544 from an inner portion of the connectionbridge to the RFID chip. Additional through holes 546, aligned with theplated through holes 532, allow for wire bond connecting the RFID chip(IC) to the plated through holes (PTH) in the module tape (MT2), henceconnecting with the contact pads (CP) on the module tape (MT2). Onlysome of the additional through holes (546) and one of the wire bonds wb3passing therethrough are shown, for illustrative clarity.

Electrostatic Discharge (ESD)

As is known, electrostatic discharge (ESD) may occur when a smart card(or transponder chip module) is being handled either during itsmanufacture or use, and may damage the electronics in the chip.

U.S. Ser. No. 14/551,376 filed 24 Nov. 2014 discusses some problemsassociated with electrostatic discharge (ESD) and proposes a solution.FIG. 30 therein is a diagram showing a contact pad array (CPA) having aconductive trace extending between the contact pads (CP) thereof.

FIG. 6 shows the contact pad array (CPA) of a transponder chip module(TCM) comprising eight contact pads (C1-C8). Two connection bridges(CBR-1, CBR-2) are shown above contact pads C1 and C5 of the contact padarray (CPA), respectively. The dark lines between the contact pads andconnection bridges represent conductive traces (CT) which may be formedfrom the same conductive layer (CL), or metal layer (ML) from which thecontact pads (CP) may be formed, such as by laser etching. Theconductive traces (CT) may extend between contact pads (CP) of thecontact pad array (CPA). The conductive traces (CT) may also extendaround the exterior of the contact pads (CP) and connection bridges(CBR).

One or more of the conductive traces (CT) may be connected with thecentral area of the contact pad array (CPA) protect againstelectrostatic discharge (ESD). This is indicated by the oval labeled“connection to ground”. Often, the central area of the contact pad array(CPA) is contiguous with the C5 contact pad, which is ground (VSS),

For electrostatic discharge (ESD) protection, the coupling frame (CF)may be connected with (linked to, contiguous with) the C5 contact padwhich is ground (earth). ESD may occur from someone touching the contactpads (CP) of the transponder chip module (TCM) and causing the RFID chipto fail. By grounding the coupling frame with the chip, the dischargecan be avoided.

The C5 pad on the face-up side of the module tape (MT) may be connected,in any suitable manner (as indicated by the “x”) with a coupling frame(CF shown in dashed lines) which may be disposed on the opposite,face-down side of the module tape (MT).

Segmenting Metal Remaining within an Etched, Planar Antenna

Planar antennas (PA) may be etched, particularly laser-etched, from aconductive layer (CL) on a module tape (MT), or other substrate, and mayfunction as a module antenna (MA) or other antenna structure (AS)incorporated into a transponder chip module (TCM).

A planar antenna PA such as shown in FIG. 7A is an example of aconductive element of a transponder chip module which may be formed froma conductive (metal) layer (such as a conductive layer or cladding on amodule tape, or a foil mounted to the module tape), and which has aninterior area which may be processed (such as by etching) to be free ofresidual metal. A coupling frame CF such as shown in FIG. 4C is anotherexample of a conductive element of a transponder chip module. Asdisclosed herein, residual metal remaining in the interior area of aconductive element (PA or CF) may be left in place and scribed (such asby laser etching) so that there are many small conductive pieces orsegments rather than one large mass (area) of metal.

An etched, planar antenna (PA) may be in the form of a rectangularspiral comprising one long track (or trace) having two ends and a numberof turns (or traces, or tracks) separated by spaces. Using laserablation, the track width may be very small, and the spaces betweenadjacent traces may also be very small. A planar antenna (PA) may beused as a module antenna (MA) in a transponder chip module (TCM). Asused herein, the term “module antenna” (MA) infers an etched planarantenna (PA) and, in most cases, an antenna structure (AS) which islaser-etched. In some descriptions set forth herein, the several tracesof the planar antenna (actually, one long spiraling trace) may bereferred to as “tracks”, the terms “trace” and “track” generally beingused interchangeably. A planar antenna (PA) may be referred to simply asand “antenna”, its function as a module antenna (MA) being evident fromthe context. And, in some cases, the planar antenna may serve as anantenna structure (AS) which is not necessarily a module antenna, orwhich is associated with a module antenna.

Laser-etching a planar antenna may be performed by etching a conductivelayer or foil on the module tape. The resulting planar antenna may bedisposed primarily in a band (rectangular annular area) in an outer(peripheral) area of the module tape, on the face-down side of themodule tape, leaving an inner (central) area of the face-down side ofthe module tape free for the RFID chip and for making interconnectionsto the contact pads (CP) on the other (face-up) side of the module tape(MT). With chemical etching, “bulk removal” of metal (conductivematerial or foil) remaining in the interior of the planar antenna isrelatively straightforward.

However, with laser etching, “bulk removal” of metal remaining inside ofthe module antenna (MA) can be time-consuming and may adversely affectthe underlying substrate (module tape).

Attention will now be directed to segmenting a conductive metal layer(ML, CL) remaining inside a laser-etched planar antenna (PA), as anexample of any laser-etched antenna structure (AS). A conductive layer(CL) comprising copper will be described, as exemplary of etching anyconductive material for a module antenna (MA). Segmenting a conductivelayer rather than performing bulk removal thereof, particularly withrespect to laser etching (or scribing) has been discussed with respectto FIG. 4C.

Removing much (or all) of the metal layer (ML) on the module tape (MT)which is remaining inside of the planar antenna (PA), may be timeconsuming, particularly when laser etching the conductive layer.Advantageously, the portion of the metal layer (ML) which is inside of(in an area internal to) the planar antenna (PA) may be segmented, suchas by laser ablation, to have several isolated conductive structures,each structure (or segment) having an area which is only a fraction ofthe area inside the planar antenna.

In laser ablating single- or double-sided glass epoxy tape to expose anantenna structure (AS), there is inevitably a bulk area of copper whichneeds to be removed. This bulk removal of copper from the surface of theglass epoxy tape takes up valuable laser time. Inasmuch as the remainingcopper is a conductive surface in the middle of the antenna, theremaining copper may significantly affect the resonance frequency andpower delivery to the RFID chip (IC). In the case of a dual interfacetransponder chip module the same applies, there is an area in the middleof the laser etched module antenna (the position of the die) which needsto be removed. On the face-up (contact pad) side of the module tape (MT)there is also a large conductive (copper) area in the middle of thecontact pad array (CPA), which is usually left in place and contiguouswith the C5 contact pad.

It may be advantageous not to bulk remove the copper from the center ofthe module antenna (MA) (or, from the center of the contact pad arrayCPA), but rather to segment the remaining copper surface by creatingslits or tracks in the copper by laser-etching, resulting in severalsmaller isolated conductive areas rather than one large conductive area.This may also be characterized as rendering the entire large area lessconductive overall, and may be referred to as “profiling” the coppersurface. Some examples will be presented.

In the examples that follow, an antenna structure (AS) is shown, on amodule tape (MT) 702 or other suitable substrate for a transponder chipmodule (TCM) 700. (The RFID chip is omitted for illustrative clarity.)The antenna structure (AS) may be an etched planar antenna (PA) 720,particularly a laser-etched antenna structure (AS), etched from aconductive layer (CL) 704 on the module tape (MT), suitable to beincorporated into a transponder chip module (TCM) as an example of anytransponder device or RFID device as the module antenna (MA) or otherantenna structure (AS) thereof. Such an antenna structure (AS) maycomprise a plurality of tracks (traces, as mentioned before, actuallyone long spiraling track) separated by spaces, disposed in a rectangularspiral pattern around a periphery of the module tape (MT). Examples ofsegmenting a portion of the metal conductive layer (CL) 704 remaining inan area inside of (interior to) the module antenna (MA) are shown.

In laser ablating single- or double-sided glass epoxy tape to expose anantenna structure (AS), there is inevitably a bulk area of copper whichneeds to be removed. This bulk removal of copper from the surface of theglass epoxy tape takes up valuable laser time. Inasmuch as the remainingcopper is a conductive surface in the middle of the antenna, theremaining copper may significantly affect the resonance frequency andpower delivery to the RFID chip (IC). In the case of a dual interfacetransponder chip module the same applies, there is an area in the middleof the laser etched module antenna (the position of the die) which needsto be removed. On the face-up (contact pad) side of the module tape (MT)there is also a large conductive (copper) area in the middle of thecontact pad array (CPA), which is usually left in place and contiguouswith the C5 contact pad.

It may be advantageous not to bulk remove the copper from the center ofthe module antenna (MA) (or, from the center of the contact pad arrayCPA), but rather to segment the remaining copper surface by creatingslits or tracks in the copper by laser-etching, resulting in severalsmaller isolated conductive areas rather than one large conductive area.This may also be characterized as rendering the entire large area lessconductive overall, and may be referred to as “profiling” the coppersurface. Some examples will be presented.

In the examples that follow, an antenna structure (AS) 900 is shown, ona module tape (MT) 902 or other suitable substrate. The antennastructure (AS) may be an etched planar antenna (PA), particularly alaser-etched antenna structure (AS), etched from a conductive layer (CL)904 on the module tape (MT), suitable to be incorporated into atransponder chip module (TCM) as an example of any transponder device orRFID device as the module antenna (MA) or other antenna structure (AS)thereof. Such an antenna structure (AS) may comprise a plurality oftracks (traces, as mentioned before, actually one long spiraling track)separated by spaces, disposed in a rectangular spiral pattern around aperiphery of the module tape (MT). Examples of segmenting a portion ofthe metal conductive layer (CL) 904 remaining in an area inside of(interior to) the module antenna (MA) are shown.

FIG. 7A shows an etched planar antenna (PA, or antenna structure AS, ormodule antenna MA) 720 on a module tape (MT) 702 wherein the conductivelayer 704 remaining at the interior area of the antenna (within theturns of the antenna) comprises a single large, residual conductivestructure. This constitutes a “baseline” configuration, and having sucha large area conductive structure within an interior area of the antennamay interfere with the operation of the antenna structure. Usingchemical etching, the residual metal within the interior of the antennais readily removed, along with forming the tracks (traces) of theantenna. However, using laser etching, it is generally not practical toremove such a large area of metal.

The planar antenna may be in the form of a rectangular spiral patternhaving a track exhibiting a number of turns and having a plurality oftraces separated by spaces. The terms “track” and “trace” may be usedinterchangeably herein, it being understood that there is one longspiraling track exhibiting a number of turns and having a plurality oftraces separated by spaces (one long spiraling space).

In FIG. 4C, an opening (OP) in the coupling frame (CF) may be created(and defined) by laser etching (scribing) the inner edge (IE) of thecoupling frame, thereby electrically isolating residual metal remainingin an interior area of the conductive from the coupling frame itself.(This assumes that the residual metal in the interior area is not “bulk”removed in its entirety.) Initially, the residual metal in the interiorarea may be one large piece (large area), and may interfere with orattenuate RF coupling between the planar antenna (PA) of the transponderchip module (TCM) and an external contactless reader (FIG. 1). Asdisclosed herein, the residual metal, which has an area substantiallyequal to the entire opening in the conductive element, may be “brokenup” into many (such as at least 10) smaller pieces or segments 428, eachof the segments having an area significantly smaller than the area ofthe original residual metal, also by laser etching, thereby improvingthe coupling, and providing opportunities to tune the performance (suchas resonance of the planar antenna (PA). Similarly, the large area 704of the conductive layer (CL) remaining within the planar antenna (PA)shown in FIG. 7A may be segmented, as shown in FIGS. 7A, 7B, 7C to havemany (such as at least 10, at least 20, at least 50) smaller pieces orsegments 704 b,c,d, each of the segments (conductive elements) having anarea significantly smaller than the area of the original residual metal,also by laser etching, thereby improving the coupling, and providingopportunities to tune the performance (such as resonance of the planarantenna (PA).

FIG. 7B shows planar antenna (PA, or antenna structure AS, or moduleantenna MA) 720 on a module tape (MT) 702 wherein the conductive layer704 remaining at the interior area of the antenna structure (AS) hasbeen segmented with “low” segmentation—in this example, one slit (SL)706 extending in a first direction (horizontal, as viewed) across theremaining conductive layer, and nine slits (SL) 706 extending in another(such as perpendicular) direction (vertical, as viewed) across theremaining conductive layer, resulting in twenty (2×10, a plurality of)smaller isolated (from one another) conductive structures 704 b. Theslits (SL) may be evenly or unevenly spaced, and the resulting smallerisolated conductive structures (or “segments”) may be the same size asone another, or different sizes than one another. The slits may becreated by laser etching (or scribing). The resulting segments 704 b arerelatively small in comparison with one large conductive structure 704.There may be at least 10 (ten) segments.

The slits (SL) described herein may be formed by laser etching (or laserscribing), in a manner similar to how the slit (S) in the coupling frame(CF) may be made, but serve a different purpose (these figures aredirected to the module antenna, not to the coupling frame). Otherbenefits of using laser etching to form slits and segment largeconductive areas (isolated conductive features) into smaller conductiveareas (isolated conductive features) may also be described herein, forexample with respect to segregating isolated conductive features in anouter area of contact side metallization (CSM) from isolated conductivefeatures in an inner area of contact side metallization (CSM), such asmay be shown in FIGS. 12A-C).

Regarding isolated conductive structures (or features), when aninitially relatively large structure (or feature) is segmented into twoor more smaller structures (or features), the resulting smallerstructures (or features) may be electrically isolated from one another.Regarding these isolated conductive structures (or features), the term“metal” may be substituted for “conductive”, and the term “feature” maybe substituted for “structure”, resulting in variations such as“isolated metal structure”, “isolated conductive feature”, and the like,and may be abbreviated as “conductive feature”, and the like. Otherterms such as “isolated conductive areas” may be used to describe thesestructures/features.

FIG. 7C shows a planar antenna (PA, or antenna structure AS, or moduleantenna MA) 720 on a module tape (MT) 702 wherein the conductive layer704 remaining at the interior area of the antenna structure (AS) hasbeen segmented with “medium” segmentation—in this example, two slits(SL) 706 extending in a first direction (horizontal, as viewed) acrossthe remaining conductive layer, and ten slits 706 extending in another(such as perpendicular) direction (vertical, as viewed) across theremaining conductive layer, resulting in thirty-three (3×11, a pluralityof) smaller isolated (from one another) conductive structures 704 c. Theslits may be evenly or unevenly spaced, and the resulting smallerisolated conductive structures (or “segments”) may be the same size asone another, or different sizes than one another. The slits may becreated by laser etching (or scribing). The resulting segments 704 c arerelatively small in comparison with one large conductive structure 704.There may be at least 20 (twenty) segments.

FIG. 7D shows a planar antenna (PA, or antenna structure AS, or moduleantenna MA) 700 on a module tape (MT) 902 wherein the conductive layer704 remaining at the interior area of the antenna structure (AS) hasbeen segmented with “high” segmentation—in this example, three slits 706extending in a first direction (horizontal, as viewed) across theremaining conductive layer, and nineteen slits 706 extending in another(such as perpendicular) direction (vertical, as viewed) across theremaining conductive layer, resulting in eighty (4×20, a plurality of)smaller isolated (from one another) conductive structures 704 d. Theslits may be evenly or unevenly spaced, and the resulting smallerisolated conductive structures (or “segments”) may be the same size asone another, or different sizes than one another. The slits may becreated by laser etching (or scribing). The resulting segments 704 d arerelatively small in comparison with one large conductive structure 704.There may be at least 50 (fifty) segments.

The resulting small isolated conductive structures may be on the orderof 1 mm or less, and may be used to tune the performance or alter theresonance frequency of the antenna. Also, if the isolated conductivestructures (segments) in the area inside the antenna are exposed, when auser touches them, this may change the resonance frequency of theantenna, such as to change it from approximately 18 MHz to approximately14 MHz. Similarly, the isolated conductive structures (segments) may beused to sense conditions such as humidity.

Although the actual amount of copper removed may be quite small (theslits may be less than 100 μm wide), several benefits may accrue tosegmenting the conductive layer material within a module antenna (MA),or other comparable antenna structure (AS). This may include beneficialeffects on the associated module's resonance frequency (it can beshifted), less signal attenuation due to smaller eddy currents in thesegmented embodiments, and the like. Some benefits accruing to profilingthe copper surface may include the ability to tune the resonancefrequency of the antenna circuit (the module antenna and whatever it isconnected to, such as the RFID chip, which has a characteristic inputcapacitance) by the number of slits, and resulting isolated conductiveareas which are created. This may make it possible to tune an antennastructure (AS, MA) to a specific RFID chip having a given inputcapacitance. As the input capacitance of RFID chips stemming from wafersproduced by a semiconductor foundry may vary from batch-to-batch,segmenting a conductive area remaining interior to (inside of) a moduleantenna (MA) may make it possible to tune the module antenna preciselyfor a given wafer batch or for a given chip set. Antenna structures (AS)may be tuned, without changing the antenna geometry itself.

By profiling or segmenting remaining metal in the inside area of theantenna (rather than performing bulk removal), the resulting antenna canbe tuned, such as altering (reducing or increasing) its resonancefrequency when it is loaded with an RFID chip having a low or high inputcapacitance.

The segmenting technique shown in FIGS. 7B-D may be applied to any ofthe planar antennas disclosed herein, such as (but not limited to) theplanar antennas shown in FIGS. 4C, 9, 10B, 15A, 15B.

The segmenting technique shown in FIGS. 7B-D may be applied to aconductive element of a transponder chip module other than the planarantenna. For example, FIG. 4C shows segmenting metal remaining in aninner area of a coupling frame (CF) conductive element of a transponderchip module (TCM). Contact pads (CP) which are also conductive elementsmay also be segments, although this may not be practical. Conductivefeatures in an outer area of the module tape may also be segmented, asdisclosed for example in FIG. 15B.

Through-Hole Connections

Traditional through-hole plating of double sided tape to connect a topmetal layer to a bottom metal layer can be replaced by a technique ofmechanical pinching, pressing or laminating a metal layer at a positionon a tape where a through-hole had previously been punched, drilled orlased and then fusing the pinched, formed or indented metal layer by aprocess of lasing or welding with an opposing metal layer, beforeelectroplating. The module tape (MT) can therefore accommodate acombination of vertical interconnects and blind vias.

The substrate may be a module tape (MT) or chip carrier tape (CCT) of anantenna module (AM) or transponder chip module (TCM), as examples ofRFID devices generally.

The transponder chip module (TCM) may be a dual-interface module havingcontact and contactless interfaces.

The transponder chip module (TCM) may have a “face-up” (or “contact”)side having contact pads for a contact interface (such as ISO 7816, orUSB) and connection bridges (CBR).

The transponder chip module (TCM) may have a “face-down” (or “chip” or“bond”) having an RFID chip (IC, CM) and an antenna structure (AS)mounted thereupon. The antenna structure (AS) may be a planar antenna(PA) which may be chemically-etched or laser-etched, typically in arectangular spiral pattern having a number of turns (tracks, traces)separated by spaces, and may serve as a module antenna (MA) for thetransponder chip module (TCM).

The connections through the substrate (MT), which may be referred to as“through-hole connections” (THC), may be useful for connectingcomponents, typically via interconnect traces (IT), on the face-downside of the substrate (MT) to contact pads (CP), connection bridges(CBR) or other isolated conductive structures such as an antennastructure (AS) or a coupling frame (CF) on the face-up side of thesubstrate (MT).

According to an embodiment (example) of the invention, generally,through hole connections (THC) may be made from a portion of aconductive layer (CL) on one side of the substrate (MT) to a conductivelayer (CL) on the other side of the substrate. The conductive layers(CL) may comprise a conductive foil, such as copper, laminated with anadhesive to the relevant side of the substrate (MT). Generally, thesubstrate (MT) may be prepared with at least one opening, or “throughhole opening” (THO), extending through the substrate (MT), and at leastone of the conductive layers (CL) spanning the opening (THO) may bedeformed such as by pinching, punching, or pressing to make contact withthe conductive layer (CL) on the other side of the substrate (MT), afterwhich the conductive layers may be welded together, such as by laserwelding, spot welding, ultrasonic welding, or any suitable process forjoining the two conductive layers together within the through holeopening (THO).

FIGS. 8A, 8B, 8C are diagrams illustrating an embodiment of a method ofmaking connections through a substrate.

FIG. 8A shows a substrate which may be an epoxy-glass module tape (MT)802 such as may be used in a transponder chip module (TCM) 800. Thesubstrate may have a top side 802 a, a bottom side 802 b, and athickness of approximately 70 μm-100 μm. A process for makingconnections through the substrate will be described in a series ofsteps, presented in an exemplary order. It should be understood thatsome steps could be performed in another order than that which isdescribed.

In a first step, the substrate may be prepared with one or more openings804, which may be referred to as through hole openings (THO, or simply“holes”, or “through-holes”) whereat it is desired to make a connectedfrom a component (or interconnect trace) on one side of the substrate toa component (or interconnect trace) on the other side of the substrate.

The holes may have a cross-dimensions of approximately 400 μm-600 μm,and may be formed by punching, drilling or laser ablation, or any othersuitable process. This is similar to what was shown in FIG. 2, above,wherein “blind holes” having a cross-dimension of approximately 300μm-500 μm are formed through a module tape (MT) to facilitate wirebonding through the blind holes in the module tape (MT).

FIG. 8B shows conductive layers (CL) 810, 812 disposed on the top andbottom sides 802 a and 802 b, respectively, of the substrate 802. Agiven conductive layer may comprise a copper foil having a thickness ofapproximately 18 μm-35 mm, and may be secured to the respective surfaceof the substrate using an adhesive 811, 813, respectively. The adhesivemay have a thickness of approximately 20 μm, and may be applied in amanner that it does not invade (enter) the through-hole, although it maybe acceptable that some adhesive enters the through-hole. A suitableadhesive may be polyurethane.

The conductive layer (CL2) 810 shown in FIG. 8B disposed atop thesubstrate, such as on the “face-up” side thereof, may be patterned suchas by laser etching to comprise contact pads (CP) in a contact pad array(CPA), or connection bridges (CBR), a planar antenna (PA) or any otherisolated conductive feature which may be relevant to transponder chipmodules (TCM).

The conductive layer (CL1) 812 shown in FIG. 8B disposed below thesubstrate, such as on the “face-down” side thereof, may be patternedsuch as by laser etching to comprise interconnect traces (IT) a planarantenna (PA) or any other isolated conductive feature which may berelevant to transponder chip modules (TCM).

FIG. 8C shows that the conductive layer (CL1) 812 on one side of thesubstrate—in this example, the lower conductive layer on the bottom,face-down side of the substrate—may be deformed (indented) using anysuitable, typically mechanical technique of pinching, pressing orlaminating so that a portion of the lower conductive layer 812 which isaligned with the through-hole 804 deforms sufficiently to come intocontact with the portion of the upper conductive layer (CL2) 810 alignedwith the through-hole on the opposite side of the substrate. In otherwords, a portion of a conductive layer which spans (extends over) thethrough-hole on one side of the substrate may be deformed so as toextend through the through-hole and at least to the opposite surface ofthe substrate whereat it may contact and be joined with a conductivelayer on the opposite side of the substrate.

Alternatively, rather than simply deforming the conductive layer on thebottom, face-down side of the substrate, it may first be cut or slit atthe location of the through-hole, then portions of the conductive layerspanning the through-hole may be bent to come into contact with theconductive layer on the top, face-up side of the substrate.

Finally, a process of lasing or welding 830 may be employed to fuse theconductive layers together in the through-hole. A green laser (532 nm)may be used for welding the two conductive layers together. Theresulting structure may be electroplated. The module tape (MT) cantherefore accommodate a combination of vertical interconnects and blindvias.

For making a plurality of connections through a substrate (in thecontext of a connection bridge CBR, typically two connections throughthe substrate may need to be made), the process described herein may beused in conjunction with the process described hereinabove (wire-bondingthrough the module tape), resulting in different types of connectionsbeing made through a given substrate. A module tape (MT) for atransponder chip module (TCM) can therefore accommodate a combination ofvertical interconnects and blind vias.

FIGS. 8D, 8E, 8F illustrate an embodiment of a method of makingconnections through a substrate 800 This technique shares some stepswith the previously-described technique, and the materials and processesmay generally be the same as were described with respect to thepreviously-described technique.

FIG. 8D illustrates a first step wherein a substrate 802 such as “bare”(no cladding) glass-epoxy tape is punched to have through-holes 804, andthereafter a conductive layer 812 is disposed on only one (shown a thebottom) side thereof. For example, a copper foil could also be laminatedto the glass epoxy, such as in copper cladding. For example, theconductive layer may be disposed on the face-down side of the substrateand may be patterned to exhibit a planar antenna (PA), a coupling frame(CF), interconnect traces (IT), or any other desired isolated conductivestructure appropriate for the face-down side (for example) of atransponder chip module (TCM).

The conductive layer may then be patterned to exhibit contact pads (CP),connection bridges (CBR), a planar antenna (PA), a coupling frame (CF),interconnect traces (IT), or any other desired isolated conductivestructure appropriate for the face-up side (for example) of atransponder chip module (TCM).

Alternatively, a substrate which is a single-sided epoxy glass tapealready having a conductive layer already disposed on one side thereofmay be prepared with holes extending through the tape to expose theunderside of the conductive layer. A UV laser may be suitable forcreating the through-holes through the substrate, terminating at andexposing the conductive layer.

FIG. 8E illustrates a next step, wherein the conductive layer (such ascopper foil) is pinched, punched or pressed at the position of thethrough-hole so that it is deformed (has deformities such as bumps orhillocks, projecting upward, towards the opposite side of the substrate)to extend at least to the other surface of the substrate, and possibly afew microns (μm) beyond. This may be done using a male tool 832 and afemale tool 834 (or anvil, or die). The male tool may move against anon-movable female tool, or the female tool may also move against themale tool. In this manner, the shape (form) of the stretched copper maybe better controlled, and the surface of the conductive layer extendingthrough the through-hole may be patterned to have a non-smoothtopography for better connecting with the conductive layer subsequentlyapplied (to the top of the substrate, in the next step).

Alternatively, a foil for the first conductive layer on the bottom(face-down) side of the module tape (see FIG. 8D) may first be preparedor formed (deformed) with projections (bumps, hillocks), then laterapplied to the substrate tape, but aligning a plurality of bumps with acorresponding plurality of through-holes may present some alignmentproblems. Alternatively, rather than deforming the foil to haveprojections, projections of a conductive material (such as solder ballsor bumps) may be applied to a surface of the foil which is then joinedwith a substrate prepared with through-holes.

FIG. 8F illustrates a next step, wherein a second conductive layer 810is disposed on the opposite (in this example, top, or face-up) side ofthe substrate (module tape MT). The conductive layer may be joined tothe substrate using an adhesive 811. This conductive layer may bepatterned to exhibit contact pads (CP), connection bridges (CBR), andoptionally a planar antenna (PA), a coupling frame (CF), interconnecttraces (IT), or any other desired isolated conductive structureappropriate for the face-up side (for example) of a transponder chipmodule (TCM).

Finally, the two conductive layers may be intimately connected(mechanically and electrically) with one another using any suitabletechnique such as resistance welding, ultrasonic bonding or laserwelding 830.

The connecting techniques disclosed in FIGS. 8A-F may be applied to anyof the transponder chip modules disclosed herein.

Laser-etched Process with Through-Hole Connections

A process steps to produce Flexible Laser-etched Circuits (FLEC) withThrough-Hole Connections (THCs) for Contactless and Dual InterfaceModules used in Identification and Secure Transaction Applications maybe performed with the following sequence of steps:

0) 150 mm wide rolls of glass epoxy tape with no copper cladding oneither side (glass epoxy, thickness 70 or 110 μm) is the raw materialinput to the production process. The surface of the glass epoxy tape maybe sandblasted before application of adhesive layers.

1) A one component polyamide thermoplastic adhesive may be rolldeposited onto one side of the glass epoxy tape having a layer thicknessof approx. 20 μm. A release liner having a thickness of 25 μm may usedto protect the adhesive layer from dust and particles in theenvironment. In a next step, a second adhesive layer may be depositedonto the opposite side of the glass epoxy tape and protected by arelease liner.

2) In a next step, index hole(s), two outer sprocket holes and throughholes (Ø 300-600 μm) may be punched across the 150 mm tape, through thenow double sided adhesive coated glass epoxy tape.

3) In a next step, an electrodeposited copper foil (12 μm, 18 μm or 35μm in thickness) having a width of 140 mm may be roll laminated to anadhesive coated side of the glass epoxy tape, covering the previouslypunched holes creating a single sided copper laminated glass epoxy tapehaving a peel strength greater than 10 N/cm. The index hole(s) andsprocket holes are not covered by the copper foil

4) In a next step, the exposed copper covering each of the though-holesin the glass epoxy tape may be formed by a punch and press tool, so thatthe copper is stretched around the walls of the through-holes (pushedinto the through-holes) and extends substantially to (so as to be flushwith), including extending slightly beyond the opposite side of theglass epoxy tape. Portions of the copper which are deformed, stretchedand extending into the through-holes may be analogised to “rivets”.

5) In a next step, a second copper foil (12 μm, 18 μm or 35 μm inthickness) may be roll laminated to the other adhesive coated side ofthe glass epoxy tape, covering the holes with the formed or rivetedcopper.

6) In a next step, to create through-hole connections (THCs), theriveted copper is fused with the opposing copper layer at eachthrough-hole position on the tape.

7) In a next step, the remaining 8 sprocket holes are punched into the140 mm wide double sided tape using the previously punched sprocketholes on each side of the 150 mm tape for alignment. This means there iscopper covering the through-hole connections (THCs) and there arepunched-through index hole(s) and 10 sprocket holes across the 150 mmtape.

8) In a final step before degreasing, cleaning and plating, the featureson the face-up side (contact pads, connection bridges) and face-downside may be laser-etched. (Alternatives to laser etching—namely stampinga metal foil—to form the contact pads and connection bridges aredisclosed herein.)

A Construction for a Transponder Chip Module (TCM)

FIGS. 9, 9A show an embodiment (example) of a construction for atransponder chip module (TCM) 900. Generally, an antenna substrate (AS)comprising a module substrate (MS) 902 such as an epoxy-glass moduletape (MT) having a planar antenna (PA; or module antenna MT) formed onone side thereof may be joined to an etched or stamped metal sheet, orlayer (or tape, (or foil), which may be referred to as a leadframe (LF)950. An RFID chip (IC) 908 may be provided. Some steps for making thetransponder chip module (TCM) 900 and its various components may bedescribed in an exemplary illustrative order. It should be understoodthat some steps could be performed in another order than that which isdescribed.

Many kinds of integrated circuit packaging are made by placing a siliconchip on a lead frame, then wire bonding the chip to the metal leads ofthat lead frame. Although the stamped metal tape disclosed herein doesnot match that definition exactly, it may nevertheless be referred to asa “leadframe” since it can be manufactured using conventional leadframetechniques.

FIG. 9 shows a stamped metal layer or sheet (or tape), which may bereferred to herein as a leadframe (LF), having a plurality of isolatedconductive features such as an arrangement of contact pads (CP, C1-C8)and connection bridges (CBR-1, CBR-2). Small, generally rectangulartie-bars (tb) are shown extending from peripheral portions of theisolated conductive features to an outer portion (OP) or frame of theleadframe (LF), for supporting the arrangement of contact pads andconnection bridges, and may also be useful for subsequent electroplatingof the isolated conductive features. The tiebars may be approximately800 μm long, along a gap between the outer portion (OP) of the leadframeand external edges of the isolated conductive features. (The outerportion OP of the leadframe is shown with diagonal lines/shading.) Acentral area of the leadframe may be contiguous with the C5 contact pad,which may be “ground”. In the final product, the tie-bars tb and outerportion OP of the leadframe will be removed (excised), such as bypunching.

The metal connection bridges and ISO 7816-2 contact pads can befabricated by laser or chemical etching of electrodeposited copper(followed by metal passivation coatings) or by stamping for example 70μm thick copper foil, or a similar metal or metal alloy and laminatingthe stamped foil to the module substrate (module tape). Additionalnarrow tracks (or tabs, or tie-bars) may be provided to link one or moreof the (isolated conductive features) to the periphery of the module formechanically supporting the isolated conductive features, and may alsofacilitate an electroplating or stamping processes. One or more of thesetie-bars can remain in the final module or can be removed duringproduction of the module tape by laser etching, chemical etching orpunching.

After the leadframe is mounted to a module tape and the tie-bars arecut, the outer portion of the leadframe may be discarded, leaving onlythe inner portion having contact side metallization (CSM) on the moduletape.

FIG. 9 shows, partially, in dashed lines, the planar antenna (PA) 920,which is not part of the leadframe (LF), to illustrate its positionrelative to the isolated conductive features. FIG. 9 also shows, assmall circles, some through-holes (TH), described hereinbelow, which arenot part of the leadframe (LF), to illustrate their positions relativeto the isolated conductive features. Generally, a through hole will belocated underneath an isolated conductive feature such as a bond padwhich needs to be connected with the RFID chip or antenna on the otherside of the module tape.

FIG. 9A shows the leadframe (LF) in cross-section, being assembled(laminated) to the top (face-up) side of a module tape (MT) 902. Themodule tape may be an epoxy-glass substrate having a thickness ofapproximately 100 μm. The module tape may have a planar antenna 920 onits bottom (face-down) side. The module tape may have a central opening(CO) 904 so that an RFID chip (IC) may be mounted to a central area ofthe leadframe, through the central opening in the module tape. Themodule tape may have a number of through holes (TH) 906 so that the RFIDchip may be connected, by wire bonds extending through the throughholes, to undersides of selected ones of the contact pads on theleadframe.

In a first step, a module tape (MT) (or substrate) may be prepared witha number of through-holes (TH), aligned with at least some of thecontact pads (CP) and connection bridges (CBR) for allowing through-holeconnections to be made between components (such as module antenna MA;and RFID chip IC) on the face-down side of the module tape and theisolated conductive features on the face-up side of the module tape.These through-holes, shown as small circles in FIG. 9 (the through-holesare in the module tape, not the leadframe) may have a cross-dimension(such as diameter) of approximately 100's of microns, up toapproximately 1 mm (1000 μm). Only the through-holes along the sectionline A-A are visible in FIG. 9. A larger opening (CO) may be providedthrough the module tape (MT), for allowing an RFID chip (IC) to bemounted, “recessed” through the module tape, to the underside of thecentral area of the leadframe (LF), rather than to the bottom surface ofthe module tape, if desired.

In a next step, copper foil (or cladding), having a thickness ofapproximately 18 μm, or 35 μm, may be joined (clad, cladded, laminated)to the face-down side of the module tape (MT) and etched (such as withlaser-etching) to form a planar antenna (PA) having a number of turns(tracks, separated by spaces). The module tape (MT) with planar antenna(PA) may be considered to be an antenna substrate (AS). Single-sidedepoxy-glass tape with copper cladding on one side thereof may be used.Double-sided tape is not necessary for this embodiment.

In a next step, bond pads may be added to the module tape (MT). The bondpads may comprise little segments/pieces of ribbon tape, forming ribbonpatches or bond pads suitable for accepting wire bonding. For example, abond pad may be provided for connecting to the outer end of the moduleantenna, and another bond pad may be provided within the interior areaof the module antenna for connecting to the appropriate terminal of theRFID chip (IC).

In a next step, the antenna substrate (AS) may be joined (assembled),such as by laminating, to the underside of the leadframe (LF) andinterconnected therewith.

A central opening (CO) may be formed in the module tape (MT) so that theRFID chip (IC) 908 may be mounted to the leadframe (LF) rather thanbeing mounted on the module tape (MT). The RFID chip would typically bemounted to the leadframe after the module tape is joined to theleadframe. The leadframe may have a thickness of approximately 70 μm.The RFID chip may have a thickness of approximately 150 μm. Wire bondsextending from the RFID chip (such as through the through holes forconnecting with the undersides of contact pads) may have a loop heightof approximately 100 μm. Epoxy encapsulating the RFID chip and wirebonds may have a thickness of 50 μm, over the wire bonds.

The RFID chip may be connected with the contact pads and connectionbridges by through-hole connecting, as described herein, by wire bondingthrough holes extending through the module tape to the undersides of thecontact pads (and connection bridges). Alternatively, additional bondpads, interconnects and through-hole connections (such as through-holeplating) may be provided for connecting the RFID chip with the moduleantenna, contact pads and/or connection bridges.

Techniques for manufacturing transponder chip modules (TCM) forapplication in dual interface smartcards having two communicationinterfaces (contact and contactless) may generally comprise one or moreof the following steps:

-   -   prepare laser-etched antennas on an antenna substrate, which may        be single sided copper clad glass epoxy tape with punched holes        or openings;    -   prepare a plated metal frame having a stamped contact pad        layout, and optionally connection bridges;    -   join (or adhesively attach) the antennas to corresponding        contact pad arrangements on the metal frame to form transponder        sites;    -   mount dual-interface chips at the transponder sites; and    -   make appropriate inter-connections between the dual-interface        chips and the underside of the contact pads (and connection        bridges) on the metal frame as well as connections to the        antennas.

The laser-etched antenna may have several tracks (or turns, of one longspiral track or trace) spaced 25 μm from one another, and may be plated,such as with nickel and (or nickel/gold). Subsequent plating may reducethe spacing between the tracks of the antenna, thereby increasinginductance/capacitance of the antenna structure and improvingperformance of the antenna module.

The glass epoxy tape may have a thickness of approximately 100 μm.Alternate materials for the tape may include materials such as PyraluxorKapton B (polyimide). Some tapes may already be prepared with aconductive layer (e.g., of copper). Other tapes may require the additionof a copper layer. The copper layer may be an electrodeposited (ED)copper layer. ED copper layers are amenable to laser etching (ablation).The copper layer may have a thickness of approximately 18 μm or 35 μm.The polyimide layer made have a thickness of approximately 25 μm. Thestamped metal frame may be made of roll annealed copper selectivelyplated with nickel or nickel/gold with a thickness in the range of 70μm.

The techniques described herein are applicable to the use of a laseretched antenna structure with a stamped leadframe. The stamped leadframeis used to form the contact pads (including CBRs) from typically 70 μmthick copper. The contact pad gap and leadframe feature sizes may bechosen to be suitable for stamping, in the range 150-300 μm for example.This leadframe is then laminated, using adhesive, to the glass epoxysubstrate. The glass epoxy substrate may be a single sided copper cladlaminate, bearing our usual laser or chemically etched antennastructure.

The stamped leadframe may be spot plated with nickel/palladium,nickel/gold or nickel/palladium/gold to permit gold wire bonding of theRFID chip IC. The connections to the RFID chip IC may be made usingblind vias (as described hereinabove).

FIG. 9 shows that there may be two connection bridges (CBR-1, CBR-2)disposed above the array of contact pads (C1-C8). One CBR (CBR-1) may beused to bring the outer antenna connection (dot, “●”) inwards (past theintervening turns of the module antenna) to the position “x” to connectwith the RFID chip. However, instead of a gold wire bond or platedthrough hole, the connection may be made by a thermocompression bond (orsimilar). The second CBR (CBR-2) may be used to link the innermostantenna winding to the IC. The IC is wire-bonded through a blind via tothe CBR. The antenna may be thermocompression bonded (or similar) to thesame CBR using a second blind via.

The use of thermocompression bonding (or similar) to make the antennaconnections has the advantage that the laser etched antenna structureneed not necessarily be electroplated with nickel/gold passivationlayers, or spot plated at the connection sites. This reduces the cost ofand simplifies the manufacturing process. The bond areas may be cleanedor roughened using a laser to improve the quality of thethermocompression bond. Alternatively, a copper or aluminum (aluminium)wire bond may be used. In order to prevent oxidation of the laser etchedantenna structure during device use the module may be completely orselectively coated with a spray cast conformal coating, a UV cured epoxyor other protective film.

Stamped Leadframe Design

The stamped leadframe may comprise a 70 μm thick sheet or layer ofcopper (metal foil). Various isolated conductive features may be formedin the foil by a stamping process, separated from one another be slitsand connected with one another by tie-bars which will eventually beexcised. The feature sizes may be limited by the stamping (punching)tool. For volume production the smallest feature size may be 200 μm.

The design uses tie-bars to link the contact pads together and to theleadframe. After lamination of the leadframe to the glass epoxy thesetie-bars may be disconnected by laser etching or by a punching tool toelectrically isolate the features, which may be referred to as “isolatedconductive features” such as contact pads and connection bridges, andadditional isolated conductive features (discussed below). The shape ofthe contact pads (and connection bridges) may be established toaccommodate the spot plating positions and larger vias. The variousisolated conductive features (sans tie-bars) may be referred to as“contact side metallization” (CSM).

The connections of the chip IC to the antenna may be made with ribbontape bond pads. The leadframe may be spot plated with nickel, palladiumand gold to facilitate wirebond or other connections. The connection ofLA and LB on the chip side to the antenna terminals may be interchanged.There are a number of methods to achieve the connection, for example:

-   -   1. Use of spot plating on the terminals of the antenna. For the        outer antenna connection at CBR-1 a gold wirebond may be used. A        gold wirebond links the chip LB to CBR 1. The inner connection        may be made by direct connection of the chip IC to the antenna        end.    -   2. Use of a ribbon tape connection (or thermocompression bond),        welded to the antenna terminals and to the CBRs. This employs        the use of CBR-2 bearing two spot-plated positions. One spot is        used for the ribbon tape or wire weld, the second may be        directly wire bonded to the chip. The outer antenna connection        is brought inwards by CBR-1, the inner connection is bridged by        CBR-2.    -   3. A ribbon tape contact may be used differently. Rather than        being connected directly to the antenna and the spot plating on        the stamped leadframe, the ribbon may be only bonded to the        terminals of the antenna. In this case the ribbon may have a        surface finish such as a stack of nickel/palladium/gold that        permits wire bonding. In this case, the ribbon tape may be        welded to the antenna terminal positions and a gold wirebond        used to make the connection to both CBRs (CBR-1, CBR-2). This        means the ribbon tape becomes an alternative to spot plating of        the antenna terminals. In addition, the ribbon tape may be        placed prior to laser ablation of the module (planar) antenna.

One further note is that some of the drawings show bulk removal of thecopper on the bonding side, this is for clarity. Rather than performingbulk removal, the copper inside the area of the antenna may be left inplace, and segmented, such as either using cross-hatch patterns orstraight lines cut with the laser.

The leadframe techniques (stamping a metal sheet) disclosed herein withrespect to FIGS. 9, 9A may be applicable to the contact sidemetallization of other ones of the transponder chip modules disclosedherein, it being understood that some of the contact side metallizationsare specifically described as being formed by etching a conductivelayer.

Laser Imaging

U.S. Ser. No. 14/281,876 filed 19 May 2014, (US 20140284386 25 Sep.2014) discloses LASER ABLATING STRUCTURES FOR ANTENNA MODULES FOR DUALINTERFACE SMARTCARDS. An exemplary method of forming an antennastructure (AS) for an RFID antenna module (AM) disclosed therein maycomprise:

-   -   performing a first etch to etch at least partially through a        conductive foil to exhibit tracks separated by spaces, the        spaces being the etched portions of the foil, the tracks being        the un-etched portions of the foil; and    -   mounting the foil to a module tape (MT);    -   wherein the first etch comprises laser ablation.

An alternative process to laser ablation of electrodeposited metal foilsin flexible circuits, is known as Laser Direct Patterning (LDP). Thisprocess is used to develop features with 10 micron resolution and iscompatible with several metal types on a range of common polymersubstrates including PET, polyimide, PEN, PMMA or equivalent brandedsubstrates such as Kapton®, Upilex®, Kaladex®, Melinex® and Mylar®. Thefirst step in the process is vapor deposition of a thin metal layer(<150 nm) on the polymer substrate. Next, a UV excimer laser (e.g. 308nm wavelength) projects a photomask pattern onto the metal surface. Ahigh energy pulse delivering, for example, 1050 mJ at a repetition rateof 300 Hz can be used to expose an area up to 400 mm² with a singlelaser pulse (Coherent). Because the metal is very thin, with weak UVabsorption, the incident laser beam passes through it to the substrate.Most organic substrates, such as those listed above, will have strong UVabsorption resulting in ablation of the uppermost layer of the polymerand, co-incidentally, removal of the metal layer (e.g. copper). In thismanner, a set of features or tracks, e.g. antenna tracks, may bedefined. A reel-to-reel process may be designed such that the reel movescontinuously with respect to the laser imaging station, the motion ofthe substrate being frozen by the short 30 ns pulse duration. Subsequentelectroless or electroplated deposition of metal can be used to increasethe metal thickness and add passivation and/or finishing metal layers.

In a variation of this process, a photomask may be omitted entirely withdirect laser patterning of the thin metal coating on the substrate. Inthis case a laser spot scans or rasters the substrate to removemetallized areas and reveal the final pattern. In this manner, verysmall features can be defined (<200 nm) with the feature size ultimatelylimited by the minimum size of focused laser spot achievable.

Another alternative process to laser ablation of electrodeposited metalfoils in flexible circuits is known as Laser Direct Imaging (LDI). Thisis a variation of traditional chemical etch processing. In LDI a laseris used to image a pattern directly onto a photoresist-coated panel,eliminating the production and use of a traditional photo tool. As perlaser ablation LDI enables the size, orientation and shape of thewritten pattern to be varied as needed. A resist film designed for LDI(e.g. DuPont® Riston® LaserSeries) may be laminated or otherwisedeposited onto a metal or metal-coated substrate. The resist is thenexposed to the laser beam and cured. Subsequent development of theresist reveals the exposed pattern, following this step normal chemicaletching and plating procedures can be used. Typical commercial LDIsystems can produce 25 micron minimum feature size (Coherent) thoughfeature sizes as small as 12 micron have been reported in new systems(Orbotech Paragon™-Ultra 100).

These techniques, and variations thereof, may be used to create antennastructures for transponder chip modules.

-   -   A transponder chip module “TCM” such as described herein may        have an activation or read/write distance greater than one        centimeter without the need of a booster antenna (BA) for        inductive coupling or the need of a coupling frame (CF) for        capacitive coupling. A transponder chip module (TCM) generally        comprises a planar antenna (PA) which has been arranged or        formed by means of laser or chemical etching an antenna        structure (AS) on a suitable substrate such as a module tape        (MT) or chip carrier tape (CCT) with one or two metal layers        (single or double sided glass epoxy tape). In forming a laser        etched antenna structure (LES) on the module tape (MT), the bulk        metal area at the center of the planar antenna (PA), the        position for mounting an RFID chip, is not removed, but is        segmented to break up its conductive path. The degree of        segmentation determines the resonance frequency of the antenna        circuit when connected to the RFID chip. // In arranging the        contact pads on the module tape, the spacing between contact        pads influences the resonance frequency. Etching logos or        scribing lines on the contact pads (such as at C5) or connection        bridges (CBR) can be used for tuning of the resonance frequency.        The thickness of the contact pad metal layer is greater than the        skin depth of copper at 13.56 MHz and sufficient to avoid        blemishes or indents on its top surface should its underside be        wire bonded to facilitate an interconnection. The thickness of        the antenna metal layer is so chosen to allow rapid laser        ablation in forming the planar antenna (PA) and the connection        traces thereto. Traditional through-hole plating of double sided        tape to connect a top metal layer (face-up side) to a bottom        metal layer (face-down side) can be replaced by a technique of        mechanical pinching, pressing or laminating a metal layer over a        position on a tape where a through-hole had previously been        punched, drilled or lased and then fusing the pinched, formed or        indented metal layer by a process of lasing, bonding or welding        with the opposing metal layer, before electroplating, to create        a through-hole connection (THC). The module tape (MT) can        therefore accommodate a combination of vertical interconnects        and blind vias. The transponder chip module (TCM) may compose of        a planar antenna (PA) with capacitive stubs routed underneath        the chip (CM) to enhance performance, and may have connection        pads for the placement of a silicon capacitor. The RFID chip may        have an input capacitance of 17 pF, 30 pF, 70 pF or higher.    -   A (secondary) coupling frame on a module tape, surrounding a        planar antenna, may be closely linked with (including        overlapping) a (primary) coupling frame in the card body of a        smart card (or comparable RFID device).    -   A portion of a metal layer remaining in an area inside a laser        etched antenna structure (LES) on a module tape (MT) may be        segmented (scribed) to have several smaller isolated conductive        structures for the purpose of tuning the resonance frequency of        the antenna; methods of arranging laser-etched antenna        structures (LES) on a separate substrate and later attaching to        the module tape (MT) with contact pads, and methods of arranging        contact pads on a metal tape through stamping or etching for        later attaching to the module tape (MT) with the laser-etched        antenna structures (LES), and with subsequent assembly of the        RFID chips (ICs, CMs).    -   The planar antenna (PA) described herein may be a laser-etched        antenna structure (LES) on the face-down side of a module tape        (MT) or chip carrier tape (CCT). Elements of the laser-etched        antenna structure (LES) may reside on the face-up side of the        transponder chip module (TCM). The laser-etched antenna may        consist of multiple coil structures to regulate the electrical        parameters of resistance, capacitance and inductance. Other        types of structures and features may also be arranged or formed        on either side of the transponder chip module (TCM) such as        through the process of chemical etching. The teachings disclosed        herein with reference to a laser-etched antenna structure (LES)        may equally apply to a chemical-etched antenna structure (CES)        provided the reduced spacing between antenna tracks obtained by        laser etching can be accomplished in a chemical etch process.        Such critical dimension in spacing between tracks may be less        than 100 μm, 75 μm, 50 μm or 25 μm. In addition, track widths        may be less than 100 μm, 75 μm or 50 μm.    -   The planar antenna (PA) may be indirectly connected to the        chip (CM) through connection bridge(s) and plated through-holes;        connection bridge(s) and fused metal layers (such as described        with respect to FIGS. 8A-C, D-F); and blind vertical        interconnect(s) using wire bond(s) to make the physical        electrical connection. Some of the interconnections to the        chip (CM) may be directly connected to bond pads (BP) on the        chip (CM).    -   The planar antenna (PA) may be arranged, formed or mounted on a        separate antenna substrate and aligned to the module tape (MT)        or chip carrier tape (CCT) using index holes and or sprocket        holes. The antenna substrate made of a suitable material (e.g.        single or double sided copper clad glass epoxy tape or        metallized foil) may be adhesively attached or laminated to the        module tape (MT) with blind openings or fused metal layers to        facilitate interconnections to and from the module tape (MT) to        the antenna substrate. The antenna structures (AS) on the        antenna substrate may be formed or arranged on one or both sides        of the substrate.    -   An antenna structure (AS) with a given number of turns may have        an additional narrow track running parallel to the main        conductive track with one end of the narrow track connected to        an end position in the antenna structure. The start and end        positions of a planar antenna (PA) may be routed in such a way        that a connection bridge(s) (CBR) is no longer required.        Alternatively, wire bonds may be used as connection jumpers such        as from an end position of an outer winding of a planar antenna        (PA) to an intermediate bond pad position in the middle of the        planar antenna (PA) and an another wire bond connecting said        intermediate position to a bond pad close to an RFID chip or        directly to a bond pad on an RFID chip.    -   Transponder chip modules (TCM) may consist of several component        elements, such components may comprise of a laser ablated        antenna or antennas on a flexible or rigid substrate hereinafter        called an antenna substrate which is later attached or mounted        to the module tape (MT). Such antenna substrate may have an        opening or window to accept a chip (CM) and holes to allow for        wire bonds to be connected through the substrate to the        underside of the module tape. The laser ablated antenna may        comprise of a single coil structure having a given number of        turns (e.g. 10) with spacing between antenna tracks equal to or        greater than the width (kerf) of a laser beam (e.g. 25 μm). The        antenna may have a full number of turns or portions thereof, a        quarter, half or three quarter turn at its end for the purpose        of tuning the resonance frequency. The antenna may comprise of a        dual antenna structure (AS) with the outer winding of the first        antenna connected to the inner winding of the second antenna.        The spacing between tracks for each antenna structure (AS) may        differ to enhance the overall capacitance or to introduce a        double bell shape curve around the resonance frequency of the        transponder to capture the upper and lower side lobes. The        antenna substrate may have antenna structures (AS) on both sides        of the substrate. The width of the antenna tracks may also vary.    -   A dual interface transponder chip module (TCM) may comprise: a        double-sided chip carrier tape (CCT) or module tape (MT); a        non-perforated contact pad array (CP) or an array of isolated        conductive features which is arranged or formed on the face-up        side of the chip carrier tape (CCT); a laser-etched antenna        structure (LES) which is arranged or formed on the face-down        side of the chip carrier tape (CCT); and an RFID chip (CM)        disposed on the chip carrier tape (CCT); and may be        characterized by: the laser ablated antenna may comprise of a        single coil structure having a given number of turns (e.g. 10)        with spacing between antenna tracks equal or greater than the        width (kerf) of a laser beam (e.g. 25 μm). The antenna may have        a full number of turns or portions thereof, quarter, half or        three quarter turn at its end for the purpose of tuning the        resonance frequency. The planar antenna (PA) may comprise of a        dual antenna structure (AS) with the outer winding of the first        antenna connected to the inner winding of the second antenna.        The spacing between tracks for each antenna structure (AS) may        differ to enhance the overall capacitance or to introduce a        double bell shape curve around the resonance frequency of the        transponder to capture the upper and lower side lobes.        Components of the antenna structure (AS) may reside on the        face-up side of the chip carrier tape (CCT). The width of the        antenna tracks may also vary, and may be smaller than 100 μm, 50        μm or 25 μm.    -   A double-sided chip carrier tape (CCT) or module tape (MT) with        a non-perforated contact pad arrangement and a connection bridge        (CBR) on the face-up side and a planar antenna (PA), laser or        chemical-etched, on the face-down side may have one opening in        the chip carrier tape (CCT) which extends through the tape to a        backside position on a connection bridge (CBR) and may have a        second opening in the chip carrier tape (CCT) at a second        position on the connection bridge (CBR) which has been sealed by        fusing the metal layer of the connection bridge (CBR) with the        metal layer of the planar antenna (PA), to create a through-hole        connection (THC).    -   A coupling frame with a slit, slot or gap which may be a metal        layer (MT) or a conductive layer (CL) on a suitable substrate        which partially surrounds a transponder chip module (TCM) or a        reader chip module (RCM) residing on the same substrate or a        separate substrate. The metal or conductive layer may be a        metallized (or metalized) substrate, a module tape or a chip        carrier tape (single or doubled sided), a metal or metallized        casing for a mobile telephone, an enclosure for a battery or any        type of metal or metallized housing or packaging for RFID        enabled devices, such as a transponder chip module (TCM). The        metal or metallized housing or casing acting as the coupling        frame (CF) may incorporate a ferrite layer to offset the effects        of attenuation around the area of the transponder chip module        (TCM).    -   The track width of the antenna can be varied, from end-to-end,        to improve performance, in contrast with an antenna having a        single (constant) track width. By way of analogy, this could be        viewed as more than one antenna, each having a different track        width, connected in series with one another. As an example, a        first portion of an antenna structure (AS) may have a track        width of 100 μm, another portion may have a track width of 50        μm. Additional portions may have other track widths. The spacing        between tracks may also be varied. For example, the spacing        between some tracks may be 25 μm or less, the spacing between        some other tracks may be more than 25 μm. The ability to vary        track width and spacing may be helpful in fine-tuning the        performance of the module, with attendant benefits in activation        or read/write distance (for example).    -   A method of forming a module antenna (MA) for a transponder chip        module (TCM) may comprise: laser etching a planar antenna (PA)        from a conductive layer (CL) or metal layer (ML) on a module        tape (MT) or chip carrier tape (CCT) to have tracks separated by        spaces; and segmenting a portion of the conductive layer        (CL, ML) remaining in an area inside of the planar antenna (PA)        to comprise a plurality of small isolated conductive features        rather than a single large conductive feature. The etching step        may comprise laser etching.    -   Fusing the metal layers of a double side tape at hole positions        in the glass epoxy tape residing underneath connection bridges,        to form through-hole connections (THC).    -   In the general context of coupling frames, any metallized        surface or conductive layer which is non-transparent to        electromagnetic waves can be used to capacitive couple a        transponder chip module (TCM) with a contactless reader. The        surface, layer or substrate can be metallized plastic or paper,        a metal foil, a metal card, a metal slug in a plastic card body,        a casing on a mobile telephone, an enclosure protecting a        battery, or any type of metal or metallized housing partially        surrounding a transponder chip module (TCM) to create an RFID        enabled device.

Eliminating the Connection Bridge (CBR)

FIG. 1A shows the ISO 7816 specification for contact pads C1-C8, for an8-pad configuration. For a 6-pad configuration, the contact pads C4 andC8 may be omitted.

FIG. 1B shows an exemplary 8-pad pattern which may measure approximately11.4 mm×12.6 mm.

FIG. 1C shows an exemplary 6-pad pattern which may measure approximately8.0 mm×10.6 mm.

FIG. 2B shows a transponder chip module (TCM) having two connectionbridges (CBR-1, CBR-2), in addition to the contact pads (C1-C8). Thisfigure also shows that

-   -   the C5 contact pad (ground) may extend into a central area of        the contact pad array (CPA) 202.    -   the C5 contact pad may extend outside of a border of the contact        pad array (CPA) 202.    -   the connection bridges (CBR-1, CBR-2) extend horizontally across        the top of the C1 and C5 contact pads (ignoring the extension of        the C5 contact pad outside of the border of the contact pad        array), then extend vertically, towards the central area, into a        space between the C1 and C5 contact pads.    -   the module antenna (MA), disposed on an opposite side of the        module tape (MT) from the contact pads (CP)

As used herein, “contact pad array” (CPA) may refer only to thoseisolated conductive features on the front/top (face-up side) of themodule tape that are ISO contact pads (C1-C8), exclusive of theconnection bridges (CBR-1, CBR-2).

Laser-etched antenna structures, and benefits accruing thereto (incontrast with chemical etching) are discussed herein. A laser-etchedplanar antenna may have a long track spiralling around an area for theRFID chip, an inner end and an outer end. See, for example, FIG. 4A. Thetrack width may be 100 μm, or less. Spacing between adjacent turns ofthe antenna may be 25 μm, or less. This allows for more turns in a givenspace, in contrast with chemical etching. Other benefits of laseretching may be disclosed herein.

FIG. 9 shows that a planar antenna (dashed lines) having approximately10 turns may be disposed on the face-down side of the module tape,underneath the contact pads on the face-up side of the module tape. Amodule tape (MT) may be prepared with a number of through-holes (TH),aligned with at least some of the contact pads (CP) and connectionbridges (CBR) for allowing through-hole connections to be made betweencomponents (such as module antenna MA; and RFID chip IC) on theface-down side of the module tape and the isolated conductive features(such as contact pads and connection bridges) on the face-up side of themodule tape. These through-holes, shown as small circles in FIG. 9 (thethrough-holes, shown as dashed lines, are in the module tape, not in theleadframe) may have a cross-dimension (such as diameter) ofapproximately 100's of microns, up to approximately 1 mm (1000 μm).

Components (RFID chip 908, planar antenna 920) on the face-down side ofthe module tape may be wire-bonded through the through-holes to theundersides of contact pads and connection bridges. The connection may bemade by a thermocompression bond (or similar).

Planar Antenna Having a Modified Rectangular Spiral Geometry

“Wire bonding” is well known, and is used throughout the microelectronicindustry for interconnecting dice, substrates and output pins. Finewires, generally of aluminum or gold, 18-50μm in diameter, are attachedusing pressure and ultrasonic energy to form metallurgical bonds.Devices bonded with gold wire generally need additional thermal energy,and the bonding process may be referred to as “thermosonic” rather than“ultrasonic”. Some suggested parameters for bond wire design mayinclude:

Wire diameter/type Package type Minimum length Maximum length 33 μm goldplastic 1.3 mm 2.5 mm 33 μm gold ceramic 1.0 mm 3.2 mm 25 μm goldceramic 1.0 mm 2.5 mm 33 μm aluminum ceramic 1.0 mm 3.2 mmsource: “Bonding to the chip Face” www.ami.ac.uk/courses/topics/0268_wb/

For purposes of the ensuing discussion, the maximum practical length fora wirebond may be considered to be approximately 3 mm.

A planar antenna having several (such as 10) tracks (actually, 10 turnsof a single long track) has two ends—an outer end an inner end—and maybe arranged generally as a rectangular spiral in a band in an outer(peripheral) area on the bottom (face-down) side of the module tape.

The planar antenna may be disposed on the bottom (face-down) side of themodule tape, opposite the contact pads on the top (face-up) side of themodule tape, and may be generally located (aligned) under the contactpads. A central area on the bottom (face-down) side of the module tapemay be reserved for the RFID chip and for making through-holeconnections to the undersides of the contact pads.

The planar antenna may be formed by laser etching a conductive foil tohave a track width of 100 μm, or less, and a spacing between adjacenttracks (actually, turns of the one long spiralling track) of 25 μm, orless. This small track width and spacing may be important to routing(and fitting) many turns of the planar antenna into a confined spacesuch as, as will be seen, into the limited space on the back/bottom(face-down) side of the module tape corresponding to a space betweencontact pads C1 and C5, or C4 and C8 of the front/top (face-up side) ofthe module tape.

In the following examples, some relevant dimensions may be(approximately):

-   -   The overall module tape for a given antenna module may measure        12 mm×12 mm.    -   An RFID chip may be disposed in a central area of the module        tape. The chip itself may measure 2 mm×2 mm.    -   An area of 2 mm on all four sides of the RFID chip may be        reserved for making through hole connections from the RFID chip        to the undersides of relevant ones of the contact pads, and        encapsulating to protect the connections, resulting in a 6 mm×6        mm “connection area”    -   The planar antenna may be disposed outside of the connection        area, and may extend nearly to the periphery of the module tape.        -   This means that there may be only a space of 2-3 mm            extending around the connection area and terminating at the            periphery of the module tape whereat the planar antenna may            be located. This area may be referred to as the “antenna            area” (or zone).    -   The planar antenna itself may have 10 turns (track with 100 μm,        spacing 25 μm), resulting in a width dimension (for the 10        turns) of 1.25 mm.

FIG. 10A shows that a planar antenna may have two ends, an outer end andan inner end. For a conventional rectangular spiral antenna disposed inthe antenna area, the outer end may be disposed approximately 4 mm fromthe outer edge of the RFID chip, and the relevant bond pad on the RFIDchip to which the outer end of the antenna is connected may be a further1 mm away from the edge of the RFID chip. If attempting to wire bond theouter end of the antenna to the bond pad on the chip, a wire bond wouldneed to be approximately 5 mm long.

FIG. 10A illustrates that a long, generally rectangular planar antennahaving two ends (an outer end and an inner end) may be disposed in apath which is located in a peripheral (outer) area of the module tape,and may comprise one long track making several turns as it spiralsaround the peripheral path, each of the traces of the antenna beingseparated from adjacent traces by spaces.

The simplest, most straightforward way to connect the outer end of theantenna to the bond pad on the chip would be to wirebond it. However, a5 mm long wirebond is simply too long to be practical, useful andreliable. Contrasted with a 3 mm long wirebond (which is considered tobe the maximum practical length for a wirebond, a 5 mm long wirebonduses more wire (typically, gold wire) and takes more time to create.Additionally, it would be outside of what we have referred to theconnection area, which is encapsulated.

The conventional solution to the problem is providing a connectionbridge on the top (face-up) side of the module tape, as shown forexample in FIG. 2B. See also US 20130146670 (Infineon), particularlyFIGS. 3, 4B, 4C thereof.

By modifying the geometry of the planar antenna, the need for having aconnection bridge may be eliminated. This may generally be accomplishedby modifying the geometry of the antenna so that it extends into a spaceon the face-down side of the module tape which is free of through holes(such as shown in FIG. 2) or any other means of connecting the chip tothe ISO contact pads (such as C1 and C5, or C4 and C8) on the face-upside of the module tape, so that the outer end of the antenna may bewithin approximately 3 mm of the relevant bond pad (bp) on the RFID chipfor making a wire bond connection therewith (It being assumed, herein,that the layout of bond pads on the chip itself is not modified, so thatthe relevant bond pad is closer to the outer end of the antenna.)

FIG. 10B shows a transponder chip module 1000 having a planar antenna1020 disposed on the face-down side of the module tape (MT) 1002, andextending in a rectangular spiral pattern having disposed in a patharound a peripheral (outer) area of the module tape. The antenna isgenerally in the form of a rectangular spiral track (comprising aplurality of traces separated by spaces) having an outer end (OE) 1020 aand an inner end (IE) 1020 b. The antenna extends in a band (or path)around the periphery of the module tape, on all four sides (top, bottom,left and right, as viewed) thereof.

The antenna is in the form of a “modified” rectangular spiral. On oneside (top, as viewed), the tracks of the antenna are diverted inwards,in a U-shaped pattern 1022, towards a central area of the module tapewhereat the RFID chip 1008 may be disposed, so that the outer end 1020 a(shown as a small black square) of the antenna may be (i) closer to theRFID chip 1008, so that it can be within approximately 3 mm of therelevant bond pad on the chip, and (ii) within the connection area(encapsulation area) 1010. The inner end (shown as a small black circle)is nearer to the chip, and well within the encapsulation.

An outer area 1006 of the module tape may extend in a band approximately2 mm wide around an inner area 1004 of the module tape. The outer areamay be considered to be a rectangular annulus. The contact pads (C1-C8,not shown, see FIG. 15A, for example) may be disposed in the inner area,on a face-up side of the module tape. The planar antenna may be disposedin the outer area of the module tape, on the face-down side of themodule tape, and may extend around all four sides of the module tape, ina band approximately 1.5 mm wide. The RFID chip (IC) may be disposedcentrally in the inner area on the face-down side of the module tape.

FIG. 10B also shows through holes (TH) 1012 for making wire bondconnections between the RFID chip and the undersides of contact pads, aswas discussed in relation to FIG. 2, see also FIG. 9). The through holes(TH) and their wirebond connections will be encapsulated, forprotection. The through holes are representative of any means for makingconnections, through the module tape, to the contact pads.

With the U-shaped geometry, the outer end (OE) of the planar antenna maybe repositioned (relocated, disposed) to a more central position of themodule tape, so that it may be disposed within approximately 3 mm of arelevant bond pad on the RFID chip to which is will be wirebonded. Thismay eliminate the need for connection bridges, which may nevertheless beleft in place as isolated conductive features.

With conventional ISO contact pads, such as shown in FIG. 11A, there maybe a small space of approximately 3 mm between contact pads C1 and C5,or C4 and C8. The antenna is still a generally rectangular spiral, butits geometry has been modified (in contrast with the antenna shown inFIG. 10A) to extend into a space on the bottom/back (face-down) side ofthe module tape which is between the contact pads C1 and C5(alternatively C4 and C8), more particularly between the through holesfor connecting the chip to the undersides of contact pads C1 and C5(alternatively C4 and C8). Here, the importance having a small trackwidth (approximately 100 μm, or less) and a small spacing (approximately25 μm or less), both of which are facilitated by laser (versus chemical)etching becomes evident. In this small (confined) area between thecontact pads C1 and C5 (or C4 and C8), alternatively between theircorresponding through holes, an antenna having 10 turns will have 20turns, since it makes a “U-turn”. More particularly,

-   -   the antenna is disposed mostly in a peripheral area (antenna        area) of the module tape;    -   a portion of the antenna is “modified” to extend into the        connection area of the module tape so that the outer end of        antenna may be within approximately 3 mm of a relevant bond pad        on the RFID chip, and within the connection area which is        encapsulated, to protect a wire bond extending from the outer        end of the antenna to the relevant bond pad (bp) on the chip.    -   the inner end of the antenna is disposed at a position which is        within the innermost turn of the antenna, very close to the RFID        chip, and terminates in a pad which may easily be wirebonded        (wb) to a relevant bond pad (bp) on the RFID chip.    -   the outer end of the antenna has been “moved”, from a position        which is approximately at the outermost turn (see FIG. 10A) of        the antenna to a position (see FIG. 10B) which is within the        innermost turn of the antenna (considering the        rectangular/unmodified part of the geometry), close to the RFID        chip, and terminates in a pad which may easily be wirebonded        (wb) to a relevant bond pad on the RFID chip (and encapsulated),        without requiring a connection bridge.    -   the U-shaped portion 1022 of the planar antenna extends into a        space on the face-down side of the module tape corresponding        with a space on the face-up side of the module tape between the        two contact pads C1 and C5 (alternatively, between the two        contact pads C4 and C8).

It should be understood that the U-shaped portion 1022 generally refersto a modification of the geometry of the entire band (and turns) of theantenna, not simply to (for example) one turn thereof or only the outerend 1020 a of the antenna.

-   -   The band of the antenna shown in FIG. 10A is        rectangular-annular, and may be disposed in the outer (or        peripheral) area of the module tape on all four sides of the        module tape. The inner area of the module tape may be defined as        an area inside of (and bounded by) the innermost turn of the        antenna. The outer area of the module tape may be in the form of        a rectangular (rather than circular) annulus.    -   The band of the modified geometry antenna shown in FIG. 10B is        disposed in the outer (or peripheral) area of the module tape on        three (left, bottom, right) sides of the module tape. On the top        side of the module tape, a portion of the band of the antenna        comprising substantially all of the turns of the antenna in that        portion diverts towards a central area (or simply “center”) of        the module tape, crossing into the inner area. In this case, the        inner area may be defined as an area inside of (and bounded by)        the innermost turn of the antenna, exclusive of the U-shaped        portion.    -   the outer end of the antenna extending from an outermost turn of        the antenna may be positioned close to RFID chip in the central        area of the module tape so that it may be wire bonded to the        chip, and the resulting wire bond may subsequently covered and        protected by encapsulant (even though the main body portion of        the antenna may be outside of the encapsulant, and not covered).        Refer to FIG. 10B which shows encapsulation in a connection        area, protecting all of the connections. The inner end of the        antenna, extending from the innermost turn of the antenna, is        also readily positioned within the connection area to be wire        bonded to the RFID chip and protected by encapsulant.

It may be seen from FIG. 10B that the outer end of the antenna has beenmoved from a position which is at the periphery of the module tape to aposition which is closer to the center of the module tape (and closer tothe RFID chip). In FIG. 10A, the outer end of the antenna is outside ofthe outermost turn of the antenna. This is made possible by the U-shapeof a portion of the antenna.

As used herein, the term “center” of the module tape refers to an areawithin the inner area of the module tape, whereat the RFID chip (IC) istypically located. Hence, a showing of the RFID chip in any of thedrawings presented herein may be interpreted as indicating a centralarea of the module tape. In FIG. 9A, a “central area” of theleadframe-type contact side metallization is shown and labeled as such.

Note in FIG. 10B that the module is generally rectangular (nearlysquare) having four sides—top and bottom parallel sides, and left andright sides parallel sides. The corners are rounded. The antenna is alsogenerally rectangular, and extends in a “band” around the top and bottomand left and right peripheral portions of the module tape.

As used herein, “band” refers to a number of turns of the spirallingtrack of wire, said turns or traces separated from one another byspaces. Typically, there may be approximate 10 traces (˜100 μm)separated by 9 spaces (˜25 μm) in a band, and the band would have awidth of 1.25 mm (allowing for space outside of the inner and outermostturns, 1.35 mm).

In FIG. 10A, the band of the non-modified antenna extends substantiallyuniformly around the periphery of the module tape. The outer end of theantenna is very close to the top edge of the module tape, hence very farfrom the RFID chip at the center of the module tape. The band of theantenna runs essentially parallel to the outer edges of the module tape,on all four sides thereof.

In FIG. 10B, a representative (exemplary) top portion of the antenna ismodified to have a U-shape. (Alternatively, another portion of theantenna could be modified to have a U-shape.) The U-shaped portion ofthe top portion of the band (traces separated by spaces) is caused tohave a U-shape, as follows

-   -   from a first position “a” along the top edge (periphery) of the        module, a first “leg” portion of the U-shaped portion of the        antenna extends perpendicular to the remainder of the antenna        band, inwards a few millimetres towards the center of the module        tape.    -   then, from a second position “b” which is approximately halfway        to the center of the module tape, a “bight” (bottom, connecting)        portion of the U-shaped portion of the antenna extends        perpendicular to the first “leg” portion, across the module tape        (parallel to the insertion direction), a distance of a few        millimetres towards the right edge of the module tape.    -   then, from a third position “c” at the interior of the module        tape, a second “leg” portion of the U-shaped portion of the        antenna extends outward a few millimetres towards the periphery        of the module tape, thereafter resuming its course following the        periphery of the module tape.

Because the band of the antenna doubles back on (next to) itself in theU-shaped portion (the U-shaped portion has two side-by-side bands), thewidth of the antenna is doubled, this portion of the module antenna hastwice the width of the remainder of the antenna, having two sets ofapproximately 10 traces separated by 9 space, or 10 traces separated by18 spaces. In the limited space (or area) available (only a fewmillimetres between through holes), this argues in favor of laseretching versus chemical etching. Chemical etching may simply not be ableto achieve the narrow trace width and spacing needed to fit so manyturns of an antenna in such a limited space. This space (or area) intowhich the U-shaped portion 1022 of the antenna 1020 extends maycorrespond with a space (or area) between two contact pads such as C1and C5 on the other side of the module tape. The dashed-line boxes inthe isolated conductive features labeled C1-C3, C5-C7 in FIG. 14 areindicative of the required location of the contact pad(s) according tothe ISO standard (see FIG. 1A). The C5 contact pad typically extendswell beyond the ISO standard into the central area of the module tape,and for purposes of the descriptions set forth herein, this extension ofC5 should be ignored when describing an available space between the C1and C5.

The U-shaped portion of the antenna facilitates locating the outer endof the antenna significantly closer to an RFID chip disposed in acentral area of the module tape, thereby allowing a wire bond (wb) ofreasonable length (such as no more than 3 mm) to be made between theouter end of the antenna and the RFID chip, without a jumper (or thelike) crossing over the antenna, and without a connection bridge on theother side of the tape. The inner end of the antenna does not present aproblem, since it is located interior to the antenna and can easily beextended even closer to the RFID chip. See FIGS. 10A and 10B. TheU-shaped portion of the antenna allows for both ends of the antenna tobe wire-bonded to the RFID chip, and eliminates the need for aconnection bridge (or a “connecting structure”—Infineon).

Some alternatives or additions to the above may include one or more ofthe following:

-   -   the RFID chip may be moved higher (towards the top of the module        tape) so that is may be closer to the outer end of the antenna.    -   the bond pads on the RFID chip may be relocated so that the        relevant bond pad for connecting with the outer end of the        antenna is closer thereto.    -   the band of the antenna may be modified to have U-shaped        portions on more than only one side.    -   the innermost turn of the antenna may be made thicker (greater        than 100 μm) than the other turns of the antenna. (The thickness        of all of the turns is readily varied, using laser etching.)    -   the U-shaped portion of the antenna shown in FIG. 10B) may        extend further across the module tape, including underneath the        RFID chip, substantially all the way to the antenna band on the        opposite (e.g., bottom) edge of the module tape. The RFID chip        may sit atop such an antenna passing underneath.    -   extension antenna (or capacitive stubs) can be connected to the        inner end of the antenna and be disposed in the inner area of        the module tape.

Alternative definitions and descriptions of how the modified portion ofthe antenna extends inward, towards the RFID chip, and how far inward itextends may be presented, or may be derived or implied from thedrawings, as well as how the modification may affect RF performance. Thesize of the antenna, relative to other components of the module, may bedifferent than shown. For example,

-   -   the modification of the shape of at least (top, as viewed) side        of the antenna allows the outer end (OE) of the antenna, which        is associated with the outermost turn of the antenna, to be        positioned closer to the center of the module tape (and the RFID        chip) than the remainder of the outermost turn of the antenna.        Indeed, the outer end may be positioned closer to the center of        the module tape than many or all of the turns of the antenna,        including closer to the center than the innermost turn of the        antenna (exclusive of its end/end portion).    -   the U-shaped portion of the antenna allows the outer end of the        antenna to be positioned within the inner area of the module        tape.    -   the U-shaped portion of the antenna allows the outer end of the        antenna to be positioned within an encapsulation for the module        tape.    -   the U-shaped portion of the antenna allows the outer end of the        antenna to be positioned at a distance from the center of the        module tape (or RFID chip) which is commensurate with that of        the inner end of the antenna, which is typically within the        innermost turn of the antenna, and close to the center of the        tape. One might say that the U-shape (FIG. 10B) allows for the        outer end to be within the “unmodified” inner border (FIG. 10A)        of the antenna.

An inner border of the planar antenna may be defined as the path takenby the innermost winding (or turn) of the planar conventional(unmodified) antenna shown in FIG. 10A. In the modified version shown inFIG. 10B, it may be noted that the outer end of the antenna extendsinward, towards the chip, beyond the unmodified (or “native”) innerborder of the planar antenna (or border of the inner winding) so that itis closer to the chip for accomplishing a reliable wirebond thereto,such as within 3 mm thereof. The inner end of the antenna is also withinthe “native” inner region of the antenna in both of the conventional(FIG. 10A) and modified (FIG. 10B) versions of the planar antenna.

FIGS. 11A-11E show a transponder chip module (TCM, or simply“transponder module”, or simply “module”) having a module tape (MT),isolated conductive features such as contact pads on a face-up side ofthe module tape, an RFID chip on the face-down side of the module tape,and a planar antenna which is in the form of a modified rectangularspiral (compare FIG. 10B) on the face-down side of the module tape.

FIG. 11A is a plan view of the top (face-up) side of the transponderchip module showing 8 contact pads C1-C8, and two isolated conductivefeatures (“ICF”) which may appear to be the same as connection bridges(compare FIG. 2B, CBR-1, CBR-2), but which are not used to makeconnections.

FIG. 11B is a side edge view of the module, showing the module tape(left) and encapsulation (right)

FIG. 11C is a plan view of the bottom (face-down side) of the moduleshowing the antenna and encapsulation. Also shown (faintly) are theconnection pads (C1-C3, C5-C7 are labeled) on the other side of themodule tape. The through holes for making through hole connections arevisible, under the encapsulation, extending to the connection pads C1,C2, C3, C5, C7.

FIG. 11D is a perspective view of the module, from the bottom (face-downside), showing the antenna and encapsulation. Also shown (faintly) arethe connection pads (C1-C3, C5-C7 are labeled) on the other side of themodule tape. The through holes for making through hole connections arevisible, under the encapsulation, extending to the connection pads C1,C2, C3, C5, C7.

FIG. 11E is a plan view of the bottom (face-down side) of the moduleshowing the antenna and encapsulation. Also shown (faintly) are theconnection pads (C1-C3, C5-C7 are labeled) on the other side of themodule tape. The through holes for making through hole connections arevisible. FIG. 11E is larger version of FIG. 11B, without theencapsulation, and illustrating

-   -   a wire bond between the outer end of the antenna and a relevant        bond pad on the chip,    -   a wire bond between the inner end of the antenna and a relevant        bond pad on the chip,    -   wire bonds of relevant bond pads on the chip, through the        through holes to the undersides of the contact pads C1, C2, C3,        C5, C7.

The modified rectangular spiral antenna techniques disclosed in FIGS.10B, 11A-E may be applicable to any of the planar antennas disclosedherein.

Segmented Contact Side Metallization U.S. Pat. No. 8,100,337 (2012 Jan.24; Artigue et al., “SPS”) discloses the antenna turns (13) are situatedsubstantially outside the area covered by the electrical contacts (17),so that the electrical contacts of the terminal block do not constituteelectromagnetic shielding for the signals intended for the antenna. FIG.2 shows a plurality of protuberances 33 situated on the same side as theelectrical contacts 17 but in the area which overhangs the antenna turns13. FIG. 2 of SPS is reproduced as FIG. 12 herein.

US 20140152511 (2014 Jun. 5; Merlin et al.; “Gemalto”) disclosesconductive contact lands or tracks comprising a plurality ofperforations. See also EP 2541471. FIG. 8 is illustrative. The pluralityof perforations form areas of magnetic permeability for the antenna. Theobject is maintaining the electromagnetic permeability performancesrelative to a radio frequency communication antenna more particularlyaccording to the ISO/IEC 14443 standard. The principle mainly consistsin designing contact lands, apertured electric tracks or positioningperforations calibrated up to a maximum, on such metal parts outside thestandardized areas. To this end, the conductive contact lands or trackscomprise a plurality of perforations. The perforations may be localizedin areas different from the standardized contact lands C1-C8. FIG. 8 ofGemalto is reproduced as FIG. 13 herein.

FIG. 14 shows a conventional design of a transponder chip module 1400having a plurality of isolated conductive features (ICF) such as contactpads (C1-C8) and connection bridges (CBR), which in aggregate may bereferred to as “contact side metallization” (CSM), on the top (face-up)side of a module tape (MT) 1402, and a planar antenna (PA) 1420 on thebottom (face-down) side of the module tape. The planar antenna PA may bedisposed directly under the contact pads (and connection brides), whichmay tend to block or attenuate the RF link between the planar antennaand the external reader. The contact pads (C1-C8) and connection bridges(CBR) may extend substantially to the periphery of the module tape. Inthe main, hereinafter, the discussion may focus primarily on the contactpads, as exemplary of isolated conductive features of contact sidemetallization, and connection bridges may be discussed to a lesserextent. Although two connection bridges (CBR-1, CBR-2) may be shown inthis and in other figures, typically only one of the connection bridgeswill be used (for connecting with the outer end of the antenna), theother connection bridge may simply be a decorative isolated conductivefeature. An RFID chip (IC) may be disposed on the bottom side of thetape, and connected with the antenna and contact pads.

The antenna PA may have approximately 10 turns, a track width ofapproximately 100 μm, and a spacing between tracks of approximately 25μm. The antenna PA may be disposed in a band (or strip) in a peripheralportion (or outer area) 1406 of the module tape 1402. The outer area1406 surrounds an inner area 1404 of the module tape 1402.

The outer area of the module tape may extend in a band approximately 2mm wide around the inner area of the module tape. The outer area may beconsidered to be a rectangular annulus. The contact pads (C1-C8) may bedisposed in the inner area, on a face-up side of the module tape, butmay extend into the outer area. The planar antenna may be disposed inthe outer area of the module tape, on the face-down side of the moduletape, and may extend around all four sides of the module tape, in a bandapproximately 1.5 mm wide. The RFID chip (IC) may be disposed centrallyin the inner area on the face-down side of the module tape.

In a conventional arrangement, as illustrated by FIG. 14, the contactpads may be much larger than they need to be, and overlap the antenna onthe other side of the module tape. (The dashed-line square boxes in thecontact pads represent the minimum size required by the ISO standard.)

This may lead to attenuation of RF and reduced coupling between themodule and an external (contactless) reader. This problem is addressedby SPS (FIG. 12) and Gemalto (FIG. 13).

According to an embodiment of the invention, generally, contact sidemetallization (CSM) may be arranged so that some conductive featuresdisposed in an outer area of the module tape are isolated from someconductive features disposed in an inner area of the module tape. Theseconductive features may be referred to as “isolated conductive features”(ICF). Conductive features in the inner area of the module tape maycomprise ISO contact pads. Conductive features in the outer area of themodule tape may comprise other isolated conductive features, and mayoverlap the planar antenna (PA, or simply “antenna”) on the other sideof the module tape (MT, or simply “tape”). The connection bridges mayextend from the outer area of the module tape to the inner area thereof.In some instances, one large conductive feature which would normallyspan the inner and outer areas of the module tape may be segmented, sothat outer portions of the conductive features are electrically isolatedfrom inner portions thereof.

-   -   Generally, the inner conductive features (or inner portions of        large conductive features) may be positioned in the inner area        of the module tape to function as ISO contact pads. (See FIG.        1A)—Generally, the outer conductive features (or outer portions        of large) conductive features may be positioned in the outer        area of the module tape, and although they may not perform any        direct electrical function (making contacts or interconnects),        they may be used to tune and improve the functioning of the        planar module antenna disposed on the other side of the tape in        the outer area.    -   The outer conductive features (or outer portions of large        conductive features) may be further segmented into a plurality        of smaller outer conductive features. Segmenting may be        performed by laser etching, stamping and punching, or a        combination of stamping/punching and laser etching.

FIG. 15A shows a transponder chip module (TCM) 1500 having a module tape(MT) 1502 having contact side metallization (CSM) 1510 comprising aplurality of isolated conductive features (ICF) on a face-up surfacethereof. An outer area 1506 of the module tape surrounds an inner area1504 of the module tape. The isolated conductive features in an innerarea 1504 of the module tape may comprise eight contact pads (CP,labeled C1-C8). An RFID chip (IC, shown in dashed lines) may be providedon an opposite side of the module tape (MT), in the inner area.

A planar antenna 1520 may be disposed on an opposite side of the moduletape (MT), in the inner area.

The outer area of the module tape may extend in a band approximately 2mm wide around the inner area of the module tape. The outer area may beconsidered to be a rectangular annulus. The contact pads (C1-C8) may bedisposed in the inner area, on a face-up side of the module tape, and donot extend into the outer area. The planar antenna may be disposed inthe outer area of the module tape, on the face-down side of the moduletape, and may extend around all four sides of the module tape, in a bandapproximately 1.5 mm wide. The RFID chip (IC) may be disposed centrallyin the inner area on the face-down side of the module tape.

Two isolated conductive features resembling the connection bridgesCBR-1, CBR-2 (FIG. 14, FIG. 2B, FIG. 9) extending from an outer area1506 of the module tape to the inner area 1504 of the module tape, andare labelled ICF-1 and ICF-2 since they may not need to function asconnection bridges. As mentioned above, in the discussion of the planarantenna with a U-shaped portion (FIGS. 10B, 11A-E), the isolatedconductive features disposed above (as viewed) the contact pads may notneed to function as connection bridges. Attention will therefore bedirected mainly to the isolated conductive features that are contactpads, with particular attention to the pads C1-C3, C5-C7.

The dashed-line boxes in the isolated conductive features labeled C1-C3,C5-C7 are indicative of the required location of the contact pad(s)according to the ISO standard (see FIG. 1A), and any metallization ofthese isolated conductive features extending beyond the boxes may besuperfluous with respect to making contact with an external contactreader (see FIG. 1), but the “excess” metallization may provide otherbenefits, such as providing a surface having a uniform height across thetop surface of the tape, or for aesthetic reasons, etc.

The contact pads (C1-C8) may be disposed at an inner area 1504 of themodule tape, on the face-up side thereof. The module tape may measureapproximately 12 mm×12 mm. The inner area may measure approximately 9mm×9 mm. The inner area may be surrounded by an outer (peripheral) areaextending in a band around the periphery of the module tape and having awidth of approximately 1.5 mm. The planar antenna (PA) 1520, shown onlypartially, may be disposed on the opposite (face-down) side of themodule tape in the outer area.

To gain a perspective on the relative sizes of the various featuresdescribed herein (all dimensions are approximate):

-   -   the module tape may measure 12 mm×12 mm, or 144 mm²    -   the inner (central) area may measure 8 mm×8 mm, or 64 mm², or        30-60%, such as 45% of the total area of the module tape    -   the outer (peripheral) area may measure 2 mm wide in a 40 mm        long band surrounding the inner area and extending around the        perimeter of the module tape, or 80 mm², or 40-70%, such as 55%        of the total area of the module tape        -   the outer area surrounds and may be approximately the same            size (may have approximately the same surface area) as, or            may be larger than (have a greater surface area than), such            as 25% larger than the inner area. The outer area may be            somewhat smaller than the inner area.    -   the individual contact pads (C1-C3, C5-C7) in the inner area may        each measure approximately 2 mm×3 mm    -   the isolated conductive features in the outer area may each        measure approximately 2 mm (substantially the width of the outer        band) by approximately 3 mm, or 2 mm×3 mm, or 6 mm² each. All        (e.g., fourteen) of these outer features may measure        approximately 14×6 mm², or nearly the entire area (80 mm²) of        the outer area.

The planar antenna may be disposed on the face-down side of the moduletape, and may comprise a track spiralling around the outer area. Thetrack (or trace) may have a width of approximately 100 μm. The antennamay have approximately 10-12 turns. A space between adjacent traces (orturns) may be approximately 25 μm. For illustrative clarity, only someportions of the planar antenna may be shown, in dashed lines, in FIG.15A.

FIG. 15A further shows a slit (S) 1530 extending around the contactpads, separating and electrically isolating inner (isolated) conductivefeatures (contact pads C1-C8, or simply “inner features”) 1532 fromouter (isolated) conductive features (or simply “outer features”) 1534.The slit may be formed by laser ablation of the conductive material, andmay have a width of approximately 25 μm. Each of the outer features maycorrespond with (such as being aligned with) a given one of the innerfeatures. The outer features may be formed by starting with aconventional pattern of contact pads, such as shown in FIG. 14, andcreating the slit by laser etching (or scribing). In this manner, theouter features, which overlie the antenna on the other side of themodule tape, may be electrically isolated from the inner features andsince they have less surface area (in contrast with the large contactpads shown in FIG. 14), their negative effect on RF coupling may bereduced. The outer conductive features may be disposed exclusively inthe outer area, without encroaching on the inner area. Conversely, thecontact pads may be disposed exclusively in the inner area, withoutencroaching on the outer area. The (inner) conductive features in theinner area and the additional (outer) conductive features in the outerarea constitute the contact side metallization (CSM), or a “faceplate”of the chip module. For purposed of this discussion, the innerconductive features 1532 may all be contact pads (CP), and the outerconductive features 1534 are not contact pads and they are electricallyisolated from the contact pads.

It may be noted that slitting (or scribing) the connection bridges mayrender them useless for making the desired connection between the outerend of the antenna and the RFID chip. This is particularly pertinent tothe connection bridge (such as CBR-1, FIG. 2B) effecting a connectionbetween the outer end of the antenna and the RFID chip. By modifying thepath of the slit, or by not slitting (segmenting) the connection bridge,or by not having the slit in a small portion of the connection bridge(allowing an electrical path between an outer feature and acorresponding inner feature), this problem can be circumvented. Bymodifying the antenna geometry, as in FIG. 10B, connection bridges maybe superfluous. Hence, the outer conductive features which typically maybe used for connection bridges are described as “isolated conductivefeatures” (ICF) in FIG. 15A.

The slit extending around the inner area and the contact pads may alsopose a challenge with regard to electroplating the contact pads. Thisproblem may be circumvented by making the slit discontinuous so that thedesired isolated conductive features may be electroplated. (Tie bars, ina stamped version of the contact side metallization also serve thispurpose. See FIG. 15C.) However, if there is no direct electrical pathto the conductive features in the inner area, electroless plating may beperformed, and electroplating may be performed by making temporaryconnections with the inner conductive features with pins or probes, suchas are commonly used in semiconductor burn-in and test.

The planar antenna is disposed on the face-down side of the module tape,in the outer/peripheral area thereof, so that it may be located at leastsubstantially (including entirely) under the additional isolatedconductive (outer) features. The innermost turns of the antenna may bespaced outside of the slit, such as approximately 150 μm outside of theslit. Alternatively, a few of the inner turns of the antenna may bedisposed past the slit, under the contact pads.

FIG. 15B is similar to FIG. 15A, but some of the outer conductivefeatures, such as the “T-shaped” features in the outer area, alignedwith C2 and C6, have been further segmented into at least two additionalisolated conductive features (or segments).

FIG. 15A shows that the additional (outer) isolated conductive features(14 total) may occupy substantially the entire area of the outer area ofthe module tape. However, since they are each relatively small, they maynot adversely affect the functioning of the antenna. FIG. 15B shows thatsome of the additional isolated conductive features may be segmented, soas to be even smaller.

The outer conductive features may contribute beneficially to capacitivecoupling of the module with the external contactless reader (FIG. 1),and may be designed to beneficially affect the resonance of theunderlying antenna.

Before the slit is made, isolating the outer conductive features fromthe inner conductive features, the outer conductive features may beuseful for electroplating all of the conductive features.

When a pressing tool (not shown) is used to install the chip module in amilled out recess in a card body, the outer conductive features mayallow for force to be evenly distributed over the surface the chipmodule by a pressing tool, thereby avoiding undesirable flexing of themodule. (When formed from the same foil as the inner conductivefeatures, the outer conductive features may have the same thickness andheight as the inner conductive features.) Having relatively large outerconductive features may be beneficial in this regard.

As an alternative to having any outer conductive features, the face ofthe pressing tool may be modified to accommodate the different height ofthe module tape sans contact side metallization (outer conductivefeatures) in the outer area (versus the height of the module tape withcontact side metallization/inner conductive features in the inner area).The module tape may be transparent, or colored so that the outer area isvisible and contributes aesthetically to the appearance of the module(and subsequent smart card, for example).

Segmenting the additional isolated (outer) conductive features mayreduce eddy currents, may reduce degradation of inductive couplingbetween the planar antenna and an external reader, may improve RFperformance, and may be used to tune the resonance of the planarantenna. Here, a contrast may be made with the perforated contact padsshown in US 20140152511 (Gemalto). With perforations, although theamount of metal in a given feature (such as contact pad) may be reduced,there is still a large (area) conductive path throughout the material(around the perforations). Therefore, segmentation may have a bettereffect than perforations on the performance of the module.

By minimizing the surface area of the contact pads themselves, andhaving additional isolated conductive features which are electricallyisolated from the contact pads, the activation distance of the modulemay be improved. Power delivery (from the reader to the module) may alsobe improved.

An alternative to providing a single slit (FIG. 15A) around the contactpads may be to provide one or more additional slits around the entirecontact pad array, said additional slits being concentric with thesingle slit, resulting in the additional isolated conductive featuresbeing segmented into more smaller pieces. Several concentric slits maybe intersected by several radial slits.

An alternative to providing a slit to electrically isolate theadditional isolated conductive features from the contact pads may be tomake the additional (outer) conductive features thinner than the skindepth of copper, while maintaining the contact pads (inner conductivefeatures) thicker than the skin depth of copper.

Conventional contact pads extend substantially to the periphery of themodule tape (see FIG. 14). The concept of restricting the contact padsto an inner area of the module tape and providing additional isolatedfeatures in an outer area of the module tape may be characterized asmodifying conventional contact pads with a slit (such as shown in FIG.15A) separating the inner and outer areas of the module tape, resultingin inner portions of the contact pads which are functional contact padsand outer portions of the contact pads which no longer function ascontact pads. The outer portions may be electrically-isolated from theinner portions. The antenna may be disposed around the periphery of themodule tape, so that it located at least substantially (includingentirely) under the outer portions of the contact pads. The outerportions of the contact pads may be segmented to lessen their adverseaffect on the functioning of the module antenna (and the RF link betweenthe antenna module and an external reader).

FIG. 15C shows another embodiment of a transponder chip module 1500,similar to what was shown in FIGS. 15A and 15B. Here, the module tape isnot shown. Rather, as in the FIG. 9 embodiment, the contact sidemetallization comprising (inner) isolated conductive features which arecontact pads and the additional (outer) isolated conductive features maybe formed by a stamping process, as follows.

-   -   An outer row of tie-bars 1542 connects the additional isolated        conductive features to the leadframe (LF) 1540. As with the FIG.        11 embodiment, this outer row of tie-bars corresponds with the        periphery of the module tape. After the leadframe is mounted to        the module tape (not shown), the outer row of tie-bars may be        removed by punching.    -   An inner row of tie-bars 1544 connects the additional isolated        conductive features in the outer area with the contact pads in        the inner area. After the leadframe is mounted to the module        tape (not shown), the outer row of tie-bars may be removed by        punching, or by laser ablation. If punched, epoxy encapsulating        the RFID chip and wire bonds may fill any resulting holes        through the module tape.

In this process, the slit 1530 may be stamped rather than laser etched(FIG. 15A). Stamping may result in a slit width of 100-200 μm, incontrast with a laser etched slit width of 25 μm which may be achievedusing laser etching.

In this process, slits or lines may be stamped into the overall designcomprising contact pads and additional isolated conductive features (andoptionally, connection bridges) at the leadframe stamping stage. Thetie-bars will keep the features intact. Following assembly of theleadframe to the module tape (and following electroplating), thetie-bars can be cut using a laser. (The outer conductive features, whenconnected by tie-bars to the inner conductive features may be usefulduring electroplating.) By first stamping out the design, including theslits/cuts (and tie-bars), laser time required to produce the pluralityof separate inner and outer features (and segmented features) may bebeneficially reduced. As mentioned above, at least some of the tie-barsmay be removed by a mechanical punching operation. If punching is usedto remove the inner tie-bars (between the additional isolated conductivefeatures and the contact pads), any holes in the module tape resultingfrom the punching process may eventually be filled during encapsulationof the RFID chip and wire bonds (see, for example, FIG. 10B).

The techniques of providing contact side metallization having outerconductive features in an outer area of the module tape and innerconductive features which are contact pads in an inner area of themodule tape, such as disclosed in FIGS. 15A-C, may be applied to otherof the contact side metallizations (or contact pad arrangements)disclosed herein.

FIGS. 15D and 15E show some alternate embodiments of contact sidemetallization (CSM) which may comprise contact pads (CP, C1-C8),connection bridges (CBR), and additional (outer) isolated conductivefeatures. In these embodiments, there are extensions of the contact pads(inner features) extending from the contact pads into the outer(antenna) area.

-   -   In contrast with SPS' protuberances, these extensions may be        thick (wide). The extension of the contact pad C1, for example,        is about one-half as wide as the contact pad C1. The extension        of the contact pad C2, for example, is about one-third as wide        as the contact pad C2. SPS' protuberances are very small        relative to their contact pads.    -   In contrast with SPS' protuberances, these extensions of the        inner features may occupy a substantial portion (such as at        least or greater than 50%) of the outer area. SPS' protuberances        occupy less than 50% of the outer area.    -   Some additional (outer) isolated conductive features which are        not extensions of contact pads are also shown.    -   In FIGS. 15D and 15E, there are additional (outer) conductive        features encroaching on the contact bridges (CBR), but the        contact bridges are capable of performing their intended        function (such as providing a connection between the outer end        of the antenna and the RFID chip). The connection bridges are        capable of performing their intended function (as indicated by        the dot “●” and the “x”).

FIGS. 15F and 15G show some alternate embodiments of contact sidemetallization (CSM) which may comprise contact pads (CP, C1-C8),connection bridges (CBR), and additional (outer) isolated conductivefeatures. The contact side metallizations shown in FIGS. 15D,E,F,G mayall be suitable for being formed from a conductive layer on anepoxy-glass substrate, or by stamping a metal sheet to produce aleadframe (stamped metal sheet).

In FIG. 15F, the contact pads C1-C3 and C5-C7 are rectangular, and areconventional in that they extend to the periphery of the module tape(not shown). Compare FIG. 14. The connection bridges are segmented in amanner that they may perform their intended function (as indicated bythe dot “●” and the “x”), in facilitating a connection from the outerend of an antenna disposed in the outer area of the module tape to anRFID chip disposed in the inner area of the module tape. Some additional(outer) conductive features are illustrated at the four corners of thecontact side metallization.

In FIG. 15G, the contact pads C1-C3 and C5-C7 are not rectangular, butmay be substantially the same as the conventional contact pads shown inFIG. 14. The contact pads C2 and C6 may be “T-shaped”, the bar portionof the T-shape being disposed in the outer area and extending partiallyinto outer portions of the contact pads C1/C3 and C5/C7, respectively.Although not shown, the bar portion of the T-shape may extend entirelyacross the outer portions of the contact pads C1/C3 and C5/C7,respectively.

Distinguishing over U.S. Pat. No. 8,100,337 (SPS)

U.S. Pat. No. 8,100,337 (which may be referred to herein as “SPS”)discloses double interface communication electronic module, inparticular for a chip card. FIGS. 2 and 3 are of particular interest.FIG. 2 shows contact pads and some other isolated conductive features,and protuberances 33. FIG. 3 shows antenna turns 13, and a location 21for bonding of a chip.

SPS states that “the turns 13 of the antenna are attached at theperiphery 13 (sic) of the module, in an area where they are situatedneither below nor above the electrical contacts 17 but substantiallyoutside the area delimited by the contacts.” FIG. 2 shows “a pluralityof protuberances 33 situated on the same side as the electrical contacts17 but in the area which overhangs the antenna turns 13.” It can be seenthat each contact pad has a protuberance contiguous therewith thatoverlies the antenna. Other ones of the so-called protuberances are notcontiguous with contact pads. (The word “protuberance” comes from thelate Latin word protuberare meant “to swell,” coming from the prefixpro, which means “forward,” and the root word tuber, meaning “swelling.”A protuberance may be a protuberant part or thing; a projection orbulge. A protuberance is something that extends from, and is contiguouswith something else. For example, a nose may be considered aprotuberance of a face.)

Generally, SPS has defined two areas of the module. An inner areapopulated by contact pads, and an outer area where the antenna isdisposed. Their so-called “protuberances” are all shown as beingdisposed in the outer area. Some of these “protuberances” extend fromand are contiguous with a contact pad, and are in the outer area,overlying the antenna. Many of the “protuberances” which are shown donot extend from and are not contiguous with contact pads, and thereforemay not be considered to be protuberances at all. (Simply callingsomething a protuberance does not make it one.)

SPS makes the following statements (and claims)

-   -   claim 1. An electronic module . . . having a plurality of        protuberances situated outside the area of electrical contacts        of the terminal block, on a face of the substrate opposite to        that which carries the antenna turns.    -   claim 4. An electronic module according to claim 3, wherein the        protuberances are substantially in the form of radii extending        from the electrical contacts of the terminal block towards the        periphery of the module, the total surface area of the        protuberances being small compared with the surface area of the        contacts of the terminal block.    -   Naturally, in the case where the protuberances are metal, their        total surface area must be small compared with the surface area        of the contacts of the terminal block, in order not to        reintroduce electromagnetic interference, which the novel        structure of the module has precisely made it possible to        eliminate.    -   The form of the protuberances 33 will easily be determined by a        person skilled in the art. It is possible to give the        protuberances 33 the form of slightly curved radii, as depicted        in FIG. 2. In addition, for the case where the protuberances 33        are metal (like the contacts 17), it will be useful to minimise        their surface area as much as possible. This is because they are        situated in the area overhanging the antenna turns 13 and their        surface area must be relatively small compared with the        non-metallised surface, in order to minimise any electromagnetic        interference with the antenna.

SPS' protuberances (both the ones which are contiguous with the contactpads, and the ones that are not contiguous with the contact pads) aredisposed in the outer area of the module, to have their top facesituated at the same height as the top face of the contacts 17, so thatthe pressing tool transmits the pressing force at the same time on thecontacts and on the protuberances 33, the pressing force being thustransmitted to the area of bonding of the turns 33 on the adhesive 31,without flexions or deformations of the module being able to appear.

SPS' protuberances are small. Their total surface area is small comparedwith the surface area of the contacts of the terminal block. Theirsurface area is relatively small compared with the non-metallisedsurface.

SPS' protuberances may be obstacles and/or cause wear of some readersconnectors when the card is inserted into the reader slot.

As disclosed herein, the additional isolated conductive featuresdisposed in the outer area are not contiguous with the contact pads, anddo not extend therefrom. They are physically and electrically isolatedtherefrom. Hence, these additional isolated conductive features cannotbe considered to be “protuberances” of the contact pads.

As disclosed herein, the additional isolated conductive featuresdisposed in the outer area are intentionally large. The surface area ofthe additional isolated conductive features is not small compared withthe surface area of the contact pads (contacts of the terminal block)The surface area of the additional isolated conductive features ismaximized, as much as possible, and their surface area is relativelylarge compared with the non-metallised surface. The additional isolatedconductive features may cover at least 50%, including at least 60%, atleast 70%, at least 80%, at least 90%, and nearly 100% of the outerarea, and all ranges inferred therein (such as between 50% and nearly100%, between 60% and nearly 100%, etc.).

-   -   SPS does specify a number, but states that the surface area of        their protuberances must be relatively small compared with the        non-metallised surface (i.e., in the outer area). This can        reasonably be interpreted to mean that the area of the        protuberances is less than 50% of the area of the outer area.        Some of SPS' so-called protuberances are contiguous with their        electrical contacts (contact pads), others appear to be        electrically isolated therefrom.    -   Gemalto does not specifically distinguish an outer area from an        inner area, but states that “the perforations may be localized        in areas different from the standardized contact lands C1-C8”.        The perforated (outer) area is contiguous with their contact        pads, it is not electrically isolated therefrom. The perforated        (outer) areas appear to occupy a substantial portion (clearly        more than 50%), indeed nearly all of the outer area.

As shown in FIGS. 15A and 15B, there is almost ZERO non-metallizedsurface. SPS has substantial non-metallized surface, particularly in theouter area. Although the outer area disclosed herein is mostly metal, itis broken up by electrical isolation tracks into individual pieces(additional isolated conductive features), each having small areas tominimize interfering with the function of the underlying antenna. Incontrast with Gemalto, the outer area disclosed herein, which ispopulated by conductive features which are not contact pads, may extendall the way around the entire perimeter (periphery) of the module tape,on all four sides thereof, substantially symmetrically, in a band thatis approximately 2 mm wide. The band with of 2 mm is a substantialportion, such as approximately 10-30%, of the overall width(approximately 8-13 mm, see FIGS. 1B, 1C) of the module tape. In FIG.15A, the slit separating the outer area 1506 from the inner area 1404similarly goes all the way around the module tape at a distance ofapproximately 2 mm from the outer edge thereof.

Some Features which May be Incorporated into Transponder Chip Modules

Some other features disclosed herein (some of which may have beendisclosed hereinabove) may include or relate to:

-   -   the non-removal of bulk metal such as copper from within an        inner area of a planar antenna structure on a module tape (MT)        or chip carrier tape (CCT) and profiling or segmenting said        metal area through laser or chemical etching, for tuning or        reducing the resonance frequency of the planar antenna (PA) when        loaded with an RFID chip having a low or high input capacitance.        Bulk metal such as copper from within an inner area of a        coupling frame on a module tape (MT) or chip carrier tape (CCT)        may similarly be profiled or segmented through laser or chemical        etching.    -   the arrangement or formation of non-perforated contact pads or        isolated conductive features on one side of a module tape (MT)        or chip carrier tape (CCT) and a planar antenna structure (e.g.        laser-etched antenna structure (LES) or chemical-etched antenna        structure (CES)) on an opposite side of the module tape (MT)        which forms a transponder chip module (TCM) when connected to an        RFID chip whereby the read/write performance of the transponder        chip module (TCM) is primarily determined by: the dimensions and        thickness of the non-perforated contact pads or isolated        conductive features on the face-up side of the module tape (MT),        in particular the air gap between said features, typically 200        μm; the surface area of the planar antenna (PA) on the face-down        side of the module tape (size and shape of the antenna,        thickness of the metal layer, spacing between tracks, width of        the tracks, variations in track spacing and variations in track        width and the number of turns); and the RFID chip itself, in        particular the input capacitance of the chip.    -   the arrangement of a first metal layer on the face-up side of a        module tape (MT) or chip carrier tape (CCT) and a second metal        layer on the face-down side of the tape to form a double-sided        tape, such as a copper clad glass epoxy tape with a copper layer        adhesively attached thereto or a glass epoxy tape with a first        metal layer adhesively attached to its top surface (face-up        side) and a second metal layer adhesively attached to its bottom        surface (face-down side). The thickness of the first copper        layer, e.g. 18 μm or 35 μm may be chosen to be thicker than the        skin depth of copper at 13.56 MHz, i.e. 17.7 μm while at the        same time the thickness of the copper layer may be chosen so        that the underside of said first copper layer after plating can        be wire bonded without leaving blemishes or indents on its top        surface. The thickness of the second copper layer, e.g. 18 μm        may be chosen for rapid removal of the copper during laser        ablation in forming the planar antenna structure and connection        tracks.    -   designs and orientations for connection bridges (CBR) on one        side of a module tape (MT) or chip carrier tape (CCT), effecting        connections between two components (such as an end of a        laser-etched antenna structure (LES) and a terminal of an RFID        chip (CM) or bond pad disposed on an opposite side of the module        tape (MT), and also to techniques for connecting the components        to a connection bridge (CBR).    -   techniques for selective plating (nickel, palladium, gold) over        an etched copper feature on a carrier substrate (single-sided or        double-sided tape) such as glass epoxy to expose contact pads,        connection bridges and logos on the face up side, and antenna        structures and connection tracks on the face down side.    -   techniques for creating vertical interconnects (vias) between a        metal foil layer (e.g. electrodeposited copper or roll annealed        copper) adhesively attached to a substrate such as glass epoxy        pre-preg tape with a laminated copper layer (copper clad) on its        face down side. The copper laminated pre-preg may be provided        with punch holes for later bonding of wire connections to the        underside of the adhesively attached metal foil layer (usually        Ni, Pd and Au plated) to create blind vias or for plated        through-holes. These techniques may obviate (or eliminate) the        need for plated through-holes. This may include techniques to        create vertical interconnects between two opposing metal layers        on a substrate such as module tape (MT) or chip carrier tape        (CCT) as a replacement for plated through-holes    -   techniques for alternative processes to laser ablation of        electrodeposited metal foils or roll annealed foils, for antenna        structures (module antennas), contact pad arrangements and        connection bridges for transponder chip modules (TCM).

Although the invention(s) may have been described mainly in the contextof dual-interface RFID devices, having contact (ISO 7816) andcontactless (ISO 14443) interfaces, the techniques described herein mayhave applicability to purely contactless devices, and the devices mayemploy other or additional communications interfaces.

While the invention(s) has/have been described with respect to a limitednumber of embodiments, these should not be construed as limitations onthe scope of the invention(s), but rather as examples of some of theembodiments. Those skilled in the art may envision other possiblevariations, modifications, and implementations that are also within thescope of the invention(s), and claims, based on the disclosure(s) setforth herein.

What is claimed is:
 1. A transponder chip module (TCM) comprising: amodule tape (MT); contact pads (CP) disposed on a face-up side of themodule tape; a planar antenna (PA) disposed on a face-down side of themodule tape, and extending in a band in a rectangular spiral patternaround an outer area of the module tape, wherein the antenna has aninner end (IE) and an outer end (OE); characterized in that: a portionof the band of the planar antenna extends inward, towards a central areaof the module tape, so that its outer end is not more than approximately3 mm from an RFID chip (IC) disposed in the central area; the planarantenna is laser etched as a long track having a number of turns; thetrack has a width of approximately 100 μm or less; and a space betweenturns of the track is approximately 25 μm or less.
 2. The transponderchip module of claim 1, wherein: at least the outer end of the planarantenna is connected by wire-bonding to the RFID chip.
 3. Thetransponder chip module of claim 1, wherein: the portion of the planarantenna extends into an area on the face-down side of the module tapecorresponding with an area on the face-up side of the module tapebetween two contact pads.
 4. The transponder chip module of claim 1,wherein: the inner end (IE) of the planar antenna is connected by wirebonding to the RFID chip; and the outer end (OE) of the planar antennais connected by wire bonding to the RFID chip.
 5. A planar antenna (PA)for a transponder chip module (TCM) having the form of a rectangularspiral conductive trace having several turns, an inner end (IE) and anouter end (OE), and suitable to be disposed in a rectangular annularouter area of a module tape (MT); characterized in that: a shape of atleast one side of the antenna is modified so that the outer end (OE) ofthe antenna is positioned closer to a center of the module tape than theremainder of the outermost turn of the antenna; the planar antenna islaser etched as a long track having a number of turns; the track has awidth of approximately 100 μm or less; and a space between turns of thetrack is approximately 25 μm or less.
 6. The planar antenna of claim 5,wherein: the outer end is positioned closer to the center of the moduletape than many or all of the turns of the antenna, including closer tothe center than the innermost turn of the antenna.
 7. A planar antenna(PA) for a transponder chip module (TCM) having the form of arectangular spiral conductive trace having several turns, an inner end(IE) and an outer end (OE), disposed on an annular area of a module tape(MT); wherein: the planar antenna is laser etched as a long track havinga number of turns; the track has a width of approximately 100 μm orless; and a space between turns of the track is approximately 25 μm orless.